# ![@zaelefty Avatar](https://lunarcrush.com/gi/w:26/cr:twitter::2713062530.png) @zaelefty Zachary Elliott

Zachary Elliott posts on X about if you, in the, books, science the most. They currently have [------] followers and [---] posts still getting attention that total [-----] engagements in the last [--] hours.

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### Social Influence

**Social category influence**
[social networks](/list/social-networks)  2% [technology brands](/list/technology-brands)  2% [finance](/list/finance)  1% [countries](/list/countries)  1% [celebrities](/list/celebrities)  1%

**Social topic influence**
[if you](/topic/if-you) 6%, [in the](/topic/in-the) 5%, [books](/topic/books) 5%, [science](/topic/science) 5%, [xy](/topic/xy) 3%, [youtube](/topic/youtube) 2%, [link](/topic/link) 2%, [future](/topic/future) 2%, [begin as](/topic/begin-as) 2%, [health](/topic/health) 2%

**Top accounts mentioned or mentioned by**
[@aldestrawk](/creator/undefined) [@ptelephant](/creator/undefined) [@morphotime](/creator/undefined) [@joerogan](/creator/undefined) [@wrensayschilll](/creator/undefined) [@charlesarthur](/creator/undefined) [@charles70390207](/creator/undefined) [@grok](/creator/undefined) [@winterpragma](/creator/undefined) [@melissatheterf](/creator/undefined) [@erythros473](/creator/undefined) [@bowie19872](/creator/undefined) [@thegaychrist](/creator/undefined) [@reduxxs](/creator/undefined) [@slatzism](/creator/undefined) [@elmico](/creator/undefined) [@pdxinstitute](/creator/undefined) [@leoalexart](/creator/undefined) [@pdafoot28721](/creator/undefined) [@detransanon](/creator/undefined)
### Top Social Posts
Top posts by engagements in the last [--] hours

"Imane Khelif is in the news once again. He himself now admits he has a Y chromosome and the SRY gene. This along with the other pieces of evidence reinforce that he has a male DSD called 5-ARD. See our animation on the biology of 5-ARD and our sex development chart"  
[X Link](https://x.com/zaelefty/status/2019617476221481177)  2026-02-06T03:41Z 52.1K followers, 87.2K engagements


"On Feb [--] [----] @PTElephant delivered our second baby. Another girl. Both are doing great. The little one is squeaking asleep on my chest right now ☺ Our first baby now a two and a half year old was so excited to meet her baby sister"  
[X Link](https://x.com/zaelefty/status/2022605001344843792)  2026-02-14T09:33Z 52.1K followers, [----] engagements


"Scientific sources transcript and YouTube link located here: https://theparadoxinstitute.org/videos/biology-of-dsds-5ard https://theparadoxinstitute.org/videos/biology-of-dsds-5ard"  
[X Link](https://x.com/zaelefty/status/2019618082415579233)  2026-02-06T03:44Z 52.1K followers, [----] engagements


"See @reduxx's article on this @Slatzism https://x.com/reduxx/status/2019466208483876985s=20 🚨Algerian Olympic Boxer Imane Khelif has admitted to having male sex chromosomes. In an interview with French sports outlet LEquipe Khelif confirmed he has the SRY gene carried on a Y chromosome. https://t.co/ktgz1U2NNv https://x.com/reduxx/status/2019466208483876985s=20 🚨Algerian Olympic Boxer Imane Khelif has admitted to having male sex chromosomes. In an interview with French sports outlet LEquipe Khelif confirmed he has the SRY gene carried on a Y chromosome. https://t.co/ktgz1U2NNv"  
[X Link](https://x.com/zaelefty/status/2019618314767491378)  2026-02-06T03:45Z 52.1K followers, [----] engagements


"Gender activists have in the past few years claimed that PCOS (polycystic ovarian syndrome which only females can have) is an intersex condition. Now this one claims that women with PCOS experience partial male puberty. Ovaries abnormally producing higher androgen levels is not male puberty 🤡 @wrensayschilll @elmico @zaelefty As you probably know CAH and PCOS affect XX individuals to varying degrees in terms of experiencing partial male puberty. Do you then consider them to be male in all cases as well @wrensayschilll @elmico @zaelefty As you probably know CAH and PCOS affect XX individuals"  
[X Link](https://x.com/zaelefty/status/2022600590447014002)  2026-02-14T09:15Z 52.1K followers, 14.1K engagements


"We do not all begin female We begin genetically sexed and our reproductive anatomy is undifferentiated up until the 6th week when genetics trigger differentiation of our bipotential gonads into testes or ovaries. See our animation which explores this incredible embryology"  
[X Link](https://x.com/zaelefty/status/2013938605220114491)  2026-01-21T11:35Z 52.1K followers, 26.4K engagements


"Some of the comments reminded me of the long debunked myth that inside every sperm cell is a tiny human who just scales up once implanted into the egg. This is strange because if one of the two gametes could be called a tiny human it would be the egg cell since it holds all the essential nutrients and mitochondria for the future zygote. Regardless claiming that we begin as one of the gametes is incorrect. There are no tiny humans inside sperm or egg cells. We begin as the combination of a sperm and egg cell which forms a zygote. The tiny human inside the sperm myth is an inherent"  
[X Link](https://x.com/zaelefty/status/2023144954130792724)  2026-02-15T21:18Z 52.1K followers, [----] engagements


"In just two years @PdxInstitute has published three bestselling biology books two for adults and one for children. We do everything ourselves from writing and researching to beautiful interior formatting and striking cover design. - Binary was our first bestseller a scientific exploration of how sex is universally defined across species reaching #1 for four weeks in Developmental Biology and Anatomy & Physiology. - The Sex Development Handbook was our second a first of its kind visual guide on how sex develops in humans -- from typical development to more than [--] disorders of sex development."  
[X Link](https://x.com/zaelefty/status/1991947867443859920)  2025-11-21T19:12Z 51.8K followers, [----] engagements


"You are either a male or female and both your physical and mental health depends on recognizing this fact. Whats your advice to this person https://t.co/ooQVOLLTLp Whats your advice to this person https://t.co/ooQVOLLTLp"  
[X Link](https://x.com/zaelefty/status/1992049582482628680)  2025-11-22T01:56Z 51.8K followers, 56.1K engagements


"There has been no substantive critique of my new book The Sex Development Handbook from those who disagree. I've now received my first negative review and to our surprise it does not offer any critique of the book or its scientific information nor is it a verified purchase review stating: "Zach has absolutely no background in biology genetics or medicine. He is an architectural student who is falsely presenting himself as an expert on a highly nuanced topic." Yes I was an architecture student from 2016-2021. I've always been open about my background and I still love architecture. I also"  
[X Link](https://x.com/zaelefty/status/1992087755476619723)  2025-11-22T04:28Z 51.8K followers, [----] engagements


"Yes mothers pass a recombined X to their offspring but a father passes down their X as an almost entirely intact copy from the paternal grandmother. This is because X and Y do not recombine fully. They only recombine in small regions called the pseudo autosomal regions (PAR1 and PAR2) which are tiny fractions of the X chromosome. So this means that almost all of the X chromosome is transmitted from father to daughter without any recombination with the Y. The sex chromosome: the mother passes down a single 'X' chromosome (after recombining them) but the dad passes down just an X or a Y. Does"  
[X Link](https://x.com/zaelefty/status/1992100913796833649)  2025-11-22T05:20Z 51.8K followers, 38.9K engagements


"@leoalexart This restricted recombination only occurs between X and Y. The autosomes can recombine fully. And for hair and eyes inheritance mostly comes from recombination through the autosomes"  
[X Link](https://x.com/zaelefty/status/1992138240628043887)  2025-11-22T07:49Z 51.8K followers, [----] engagements


"Gender activists claim you must have a formal degree in a subject to have expertise in it. Bad news for Darwin Da Vinci Mendel or Faraday. Also ironic considering that they will believe any man who claims to be a woman by mere declaration"  
[X Link](https://x.com/zaelefty/status/1992308735411130805)  2025-11-22T19:06Z 51.8K followers, 12.6K engagements


"Bad news for Darwin Da Vinci Mendel and Faraday who also didnt have degrees in the subjects they became experts in. Every claim comes from directly from scientific literature with an in-text citation. It also has been reviewed and fact checked by experts in pediatrics endocrinology and DSD treatment. You dont want to take a look at the actual content because youre close-minded and your heart is filled with hatred. If you took time to read it you could learn a lot of incredible information from embryology and developmental biology"  
[X Link](https://x.com/zaelefty/status/1992313949325570317)  2025-11-22T19:27Z 51.8K followers, [--] engagements


"Sex change is an evolved sexual strategy in certain species (also known as sequential hermaphroditism) that involves complete transformation of the reproductive anatomy to support the production and release of the opposite gamete type. This cannot occur in humans because we are not as anatomically and genetically plastic and have not evolved the ability to do this. At most we can alter secondary sex characteristics and physiology through cross-sex hormones but this is not a sex change in the technical sense"  
[X Link](https://x.com/zaelefty/status/1992327193226027299)  2025-11-22T20:19Z 51.8K followers, [----] engagements


"@pdafoot28721 This you pdafoot You sent me and my company a death threat this morning. Death threats are completely unacceptable no matter who they come from and are not protected speech"  
[X Link](https://x.com/zaelefty/status/1992333229035237390)  2025-11-22T20:43Z 51.8K followers, [----] engagements


"Our new children's biology book on male and female and the start of new life fosters curiosity and wonder through some of the most visually powerful illustrations you'll see @PTElephant See more info about the book and order your copy at: 🔗 http://itallbeginswithtwo.com http://itallbeginswithtwo.com"  
[X Link](https://x.com/zaelefty/status/1992368323624059259)  2025-11-22T23:03Z 51.8K followers, [----] engagements


"Through my research into over [--] disorders of sex development one truth has become inescapable: no ones sex is undefinable. Every person has a traceable path of sex development even in the rarest of cases. And this path is either sex-specific or it manifests differently depending on whether the individual is male or female. Even when the same gene is involved the outcomes differ by sex. For example a gene encoding an enzyme mutates and in males you could see the collapse of their genital development whereas in females only mild effects are observed. We only know how to treat these differences"  
[X Link](https://x.com/zaelefty/status/1992441649717182936)  2025-11-23T03:54Z 51.8K followers, [----] engagements


"It comes as no surprise that there is diversity of sex-biased gene expression in somatic tissues and thus variation within males and females. But this does not challenge the binary of male and female. It simply shows variation within males and within females. This makes evolutionary sense because gene expression adapts to ecological social and sexual niches through natural and sexual selection pressures. No one is saying that males and females cannot share any overlap of traits. But the very fact these researchers can describe within-sex variation and overlap between the two sexes is because"  
[X Link](https://x.com/zaelefty/status/1992632365726802017)  2025-11-23T16:32Z 51.8K followers, [----] engagements


""Some women are born with disorders where they cannot produce eggs and that's why I a man without a disorder am a woman.""  
[X Link](https://x.com/zaelefty/status/1992753884453044463)  2025-11-24T00:35Z 51.8K followers, 56.2K engagements


"@detransanon Lucky for you the book discusses the myriad of complex genetic networks in detail"  
[X Link](https://x.com/zaelefty/status/1992790989803815059)  2025-11-24T03:02Z 51.8K followers, [--] engagements


"Great companion books to buy or gift this holiday The first teaches how the sexes are universally defined in biology. The second teaches how the sexes develop in humans from a single cell to a fully grown male or female. https://a.co/d/7VdpzFG https://a.co/d/3KQYZ7j https://a.co/d/7VdpzFG https://a.co/d/3KQYZ7j"  
[X Link](https://x.com/zaelefty/status/1993047179116921121)  2025-11-24T20:00Z 51.8K followers, [----] engagements


"Uterine transplant for males ignores many things. Aside from the moral issues there are a host of biological problems. Males are not built for a uterus or growing a baby on multiple levels including the structure of the skeleton organ positions hormones and blood volumes"  
[X Link](https://x.com/zaelefty/status/1993190792018772012)  2025-11-25T05:31Z 51.8K followers, 27.8K engagements


"I do not say what I feel is right either. Every claim I make in my published work is backed with an in-text citation referencing a peer-reviewed scientific article or textbook. @zaelefty The reason why peple like Darwin are respected science figures is because they contradicted the scientific consensus by using unquestionable facts sourced data and logic. They didn't just say what they "felt" was right despite the evidence of the contrary @zaelefty The reason why peple like Darwin are respected science figures is because they contradicted the scientific consensus by using unquestionable facts"  
[X Link](https://x.com/zaelefty/status/1993550753567588485)  2025-11-26T05:21Z 51.8K followers, [----] engagements


"Intersex people are males or females who have a developmental disorder of the reproductive system that has serious health impacts. So serious in fact that they need sex-specific treatment. Some would die without it. The irony is if you do not recognize this fact and instead believe they are neither male nor female and simply have a healthy variation then you are pushing a belief system that would actually result in higher rates of death among such people"  
[X Link](https://x.com/zaelefty/status/1993557872077074487)  2025-11-26T05:50Z 51.8K followers, 25.5K engagements


"A key component of gender ideology is amplifying ethnic differences while downplaying sex differences. The motivation comes from a deep belief that sex is socially constructed and that we can see this evidence through how people's bodies from different ethnicities are "policed" to conform to a binary standard. This is why you will see some activists claiming that women of color cannot be reliably classified as female because "female" is a white supremacist construct that does not accept the variation between ethnicities. This ironically is very racist. And it's also a lie. Ethnic differences"  
[X Link](https://x.com/zaelefty/status/1993729959852974406)  2025-11-26T17:13Z 51.8K followers, [----] engagements


"Female development is an active pathway that requires many complex genetic networks. One disorder that teaches us this is called Turner Syndrome where a female develops with only one X chromosome (45:X) instead of two commonly resulting in ovarian development failure and heart defects among other side effects. A common assumption is that ovaries will develop in the absence of the Y chromosome but two X chromosomes must also be present. While genes on the autosomes WNT4 FOXL2 and RSPO1 initiate differentiation of the gonads into ovaries two Xs are required to maintain this pathway. But this"  
[X Link](https://x.com/zaelefty/status/1993765516532695499)  2025-11-26T19:35Z 51.8K followers, [----] engagements


"@Ash_Lee_IRL Its not that exaggerated but sex can still be determined with 99-100% accuracy just through analysis of the skeleton"  
[X Link](https://x.com/zaelefty/status/1993767632911167965)  2025-11-26T19:43Z 51.8K followers, [----] engagements


"@HatzKatzn @eryk6741 @grok They said in response to me "then should intersex people just k*** themselves""  
[X Link](https://x.com/zaelefty/status/1993887807212015767)  2025-11-27T03:41Z 51.8K followers, [---] engagements


"Saying undifferentiated anatomy is female anatomy is like saying a block of unshaped marble is actually a statue. Embryos dont begin with female or male anatomy. Up until the 6th week the anatomy exists in a neutral state before being shaped into the male or female system"  
[X Link](https://x.com/zaelefty/status/1994650310409912688)  2025-11-29T06:11Z 51.8K followers, 18.4K engagements


"Ill help you start. What are ovaries What are testes What is even female and maleanatomy other than social classification What is even female and maleanatomy other than social classification"  
[X Link](https://x.com/zaelefty/status/1994824053539078582)  2025-11-29T17:41Z 51.8K followers, 44.8K engagements


"Let's define these terms shall we I will show that the male-female binary is simply reinforced by this diversity. Monoecious: A sexual system where an individual plant has separate male and female flowers. Dioecious: A sexual system where an individual plant is male or female (male plants produce only male flowers; female plants produce only female flowers). Hermaphroditic plants: A sexual system where an individual plant has both male and female within the same flower. Sequential hermaphrodites: A sexual system where an individual organism can switch from male to female or female to male or"  
[X Link](https://x.com/zaelefty/status/1994981076536553676)  2025-11-30T04:05Z 52K followers, 17K engagements


"Ovaries produce eggs and are comprised of follicles along with Granulosa cells and Theca cells. Testes produce sperm and are comprised of seminiferous tubules along with Sertoli cells and Leydig cells. But yeah other than that totally the same thing. @zaelefty The same thing @zaelefty The same thing"  
[X Link](https://x.com/zaelefty/status/1995036242619371773)  2025-11-30T07:44Z 51.8K followers, 22.2K engagements


"@Mamumanda18 Ovaries produce eggs and are comprised of follicles along with Granulosa cells and Theca cells. Testes produce sperm and are comprised of seminiferous tubules along with Sertoli cells and Leydig cells. But yeah other than that totally the same thing"  
[X Link](https://x.com/zaelefty/status/1995036617665646782)  2025-11-30T07:46Z 51.8K followers, [----] engagements


"Testes do not start as ovaries. Both ovaries and testes originate from bipotential tissue that then differentiates down one or the other path due to sex-specific genetic signals. If you have XY the SRY gene on the Y chromosome triggers the SOX9-FGF9 feedback loop which differentiates the bipotential tissue into testes. If you have XX autosomal genes WNT4 FOXL2 and RSPO1 along with double dose escape genes from the two Xs differentiate the bipotential tissue into ovaries. @zaelefty Both are the same part of the body but changed by the sexes 🙄 Testicles are fucking ovaries who produce"  
[X Link](https://x.com/zaelefty/status/1995178103677571326)  2025-11-30T17:08Z 51.8K followers, 25.3K engagements


"A review of my new book on how humans develop as male or female The Sex Development Handbook. As a biologist this book is essential and filled with clarity. I was in awe of how it cascaded in beautiful detail. From the evolution of sex based on anisogamy that spans all species to specifically human sex differentiation. Given the climate we live in society has been veering away from science. This book gives me hope. Its concise color coded and has easy to follow diagrams for ANY skill set. It is truly a visual guide and scientifically rigorous. https://a.co/d/iTE4ArC https://a.co/d/iTE4ArC"  
[X Link](https://x.com/zaelefty/status/1996611069763035411)  2025-12-04T16:02Z 51.8K followers, [----] engagements


"I do not speak for anyone. I relay what the scientific evidence says to help any person who is interested in learning. And I always cite the evidence. You can take it or leave it. @zaelefty You do not speak for us Zachary. @zaelefty You do not speak for us Zachary"  
[X Link](https://x.com/zaelefty/status/1996638222454346228)  2025-12-04T17:50Z 51.8K followers, 14.9K engagements


""Non-profit" does not mean the organization is prohibited from making money or selling products or services. Those services have to further the organization's mission. Revenue generated from such things are then used to also further the mission of the organization. If non-profits were not allowed to generate revenue they could not exist in any meaningful capacity. @zaelefty LOL it's an anonymous doll collector who says they're a biologist in an Amazon review @zaelefty . Who are the Paradox Institute's donors Why does your "nonprofit" sell publisher services @zaelefty LOL it's an anonymous"  
[X Link](https://x.com/zaelefty/status/1996985608581853495)  2025-12-05T16:50Z 51.8K followers, [----] engagements


"@WinterPragma First it covers in detail [--] representative DSDs that best represent both major DSDs (in terms of incidence) and illustrative DSDs (that help us understand mechanisms). Then it also features a glossary of [--] DSDs all in one useful table. So almost every single DSD is there"  
[X Link](https://x.com/zaelefty/status/1996988538038944053)  2025-12-05T17:02Z 51.8K followers, [--] engagements


"We all begin with bipotential gonads before genetic signals upregulate one path and suppress the opposite sex path. Our default is not female but a mutual antagonism. Both testis and ovarian development involve pathways of distinct factors that act antagonistically. In XY individuals SRY initiates a positive feedback loop between SOX9 and FGF9 which up-regulates FGF9 and represses WNT4 leading to establishment of the male (testis) pathway. In XX individuals no SRY is present and WNT4 represses the positive feedback loop between SOX9 and FGF9 allowing the female (ovarian) pathway to become"  
[X Link](https://x.com/zaelefty/status/1997551005647462410)  2025-12-07T06:17Z 51.8K followers, [----] engagements


"This is false. Every embryo is genetically sexed from conception and begins physically undifferentiated. All embryos begin by developing undifferentiated gonads undifferentiated genitalia and a cloaca before genetics differentiate us down the male or female pathway. There is no transforming of female anatomy into male anatomy. In fact developing as a female is an active gene-directed path of differentiation just like being male. This was found in genetic studies showing that WNT4 FOXL2 and RSPO1 are required for ovary development WNT and HOX genes are required for developing female genitalia"  
[X Link](https://x.com/zaelefty/status/1997736727612699021)  2025-12-07T18:35Z 51.8K followers, [----] engagements


"Correct chromosomes are not always XX or XY. But when such chromosomal disorders occur they still result in males or females due to genetics. Male and female are defined as the body plans organized around the production and release of sperm or eggs. A few examples below. @Heather_pw @SianHerfield @belstarion79 @garylfrancione Chromosomes arent always XX or XY. About [--] in [----] babies is born with intersex traits (e.g. XXY XO androgen insensitivity) meaning sex isnt always strictly M or F. @Heather_pw @SianHerfield @belstarion79 @garylfrancione Chromosomes arent always XX or XY. About [--] in 2000"  
[X Link](https://x.com/zaelefty/status/1997894418083508642)  2025-12-08T05:02Z 51.8K followers, 12K engagements


"Parents and educators 🤓 Our beautiful new children's book by @PTElephant explains male and female biology in a simple age-appropriate way: how males make sperm females make eggs and how life begins in humans animals and plants. Order at 🔗 http://itallbeginswithtwo.com http://itallbeginswithtwo.com"  
[X Link](https://x.com/zaelefty/status/1998430546662183079)  2025-12-09T16:32Z 51.8K followers, [----] engagements


"We received a comment on our video on sexing the skeleton. Heres my response for educational purposes. Those with CAIS do not develop a male-typical skeletal structure. They develop skeletons that are more female-typical because they cannot respond to any testosterone and convert large amounts of it into estrogen causing pelvic widening breast development and feminine fat distribution. Further below is the evidence for Y chromosomes relationship to height. It is nuanced. It is not Y directly causes a male skeleton. The only known height related gene on the Y chromosome is SHOX a gene located"  
[X Link](https://x.com/zaelefty/status/1998804419593326668)  2025-12-10T17:18Z 51.8K followers, [----] engagements


"The Sex Development Handbook is a top bestseller sitting at #2 in Embryology. It's currently on sale for 20% off. Get your copy before the end of December and learn how males and females develop from typical development to [--] DSDs. Order on Amazon: https://a.co/d/0oAdpnm https://a.co/d/0oAdpnm https://a.co/d/0oAdpnm https://a.co/d/0oAdpnm"  
[X Link](https://x.com/zaelefty/status/1998829291597918380)  2025-12-10T18:56Z 51.8K followers, [----] engagements


"The best evidence for Y chromosome genes *directly* causing taller height in males comes from the SHOX gene. It is found in both the X and the Y chromosome. In XX females the second copy of SHOX is partially inactivated lowering transcription rates compared to XY males. The level of transcription seems to account for around 22% of the variance in the height sex difference between men and women. Studies on XYY males show a taller height on average compared to XY males and this is likely due to having a third copy of the SHOX gene. Cases of the rare XX males tend to be shorter than XY males and"  
[X Link](https://x.com/zaelefty/status/1998892144048713777)  2025-12-10T23:06Z 51.8K followers, [----] engagements


"Our new children's book on male and female by @PTElephant reached #1 in Children's Biology Books Dr. Travis Morrell writes "This book is beautiful and the art is fun. It captures the wonderthe miracleof life in an age-appropriate way. Unlike some other kids books it isnt fake or lazy scienceits real There are fascinating details most adults are not going to believe but human life really is that complex and wonderful. Lastly the book quality is high colors vibrant paper thick and glossy. I am a physician and a parent and was impressed from both angles" --@MorrellMDmph Order a copy for your"  
[X Link](https://x.com/zaelefty/status/1999719354561098145)  2025-12-13T05:53Z 51.8K followers, [----] engagements


"Sex is binary and even in cases of XX/XY sex can still objectively determined. In these cases the development of the persons sex depends on the distribution of the cell lines. Development of testes or ovaries requires a specific threshold of XY or XX cells respectively. Studies show that fewer Y-containing cells are needed to trigger testes development making the XY pathway easier to initiate (Madan 2020). Because of this variation in cell distribution many humans with XX / XY chimerism can develop as typical males or females. For example a male was referred to a clinic for infertility."  
[X Link](https://x.com/zaelefty/status/2000026000407548334)  2025-12-14T02:12Z 52K followers, 19.1K engagements


"Learn why the we all begin female myth is false in this written version of my recent video. Every claim has a linked paper where you can read more Our Substack will be the new home for all our written content. Subscribe so you dont miss anything. https://open.substack.com/pub/theparadoxinstitute/p/debunking-we-all-begin-female-paradoxr=dxzz7&utm_medium=ios https://open.substack.com/pub/theparadoxinstitute/p/debunking-we-all-begin-female-paradoxr=dxzz7&utm_medium=ios"  
[X Link](https://x.com/zaelefty/status/2000258187820413104)  2025-12-14T17:34Z 52.1K followers, [----] engagements


"@WinterPragma Mostly free. There will be some things in the future such as detailed analysis of scientific papers long excerpts from our books and long deep dives into more technical topics that will be paywalled but the base educational content will be free"  
[X Link](https://x.com/zaelefty/status/2000602956249669805)  2025-12-15T16:24Z 51.8K followers, [--] engagements


"A new paper in the Journal of Medical Ethics argues that the major harms of female genital mutilation (or FGM) do not come from the practices themselves but from those who oppose those evil practices painting anti-FGM efforts as a "heavily racialized and ethnocentric framework" that is replete with trauma-inducing practices. This is one of the most morally bankrupt papers I have ever seen. I will be releasing a video response on the moral failings of this paper very soon. Thank you to @PTElephant for alerting me to this. Link to paper:"  
[X Link](https://x.com/zaelefty/status/2000723032394928522)  2025-12-16T00:21Z 52K followers, 24.6K engagements


""Ones sex is determined at conception by the individuals genetic profile developed in utero and immutable." Subscribe to our new home for all our written content. Two articles a week on the biology of male and female https://read.theparadoxinstitute.org/p/defining-vs-determining-sex https://read.theparadoxinstitute.org/p/defining-vs-determining-sex"  
[X Link](https://x.com/zaelefty/status/2001063721410367572)  2025-12-16T22:55Z 52K followers, [----] engagements


"Sex can be identified with up to 98% accuracy from the pelvis alone 80-90% from the skull alone and almost always 100% accuracy from combining multiple skeletal traits together. See our latest Paradox Proofs video on determining sex from the skeleton https://www.youtube.com/watchv=Xf5YY_J4IxU https://www.youtube.com/watchv=Xf5YY_J4IxU"  
[X Link](https://x.com/zaelefty/status/2001120073038148029)  2025-12-17T02:39Z 51.8K followers, 25.5K engagements


"A new paper in the Journal of Medical Ethics argues that the major harms of female genital mutilation (or FGM) come from those who oppose those evil practices. I respond to its moral evils in this episode of Paradox Proofs. https://youtu.be/OXlvFo_Tnaosi=aQX8sGKBh01zG2aj https://youtu.be/OXlvFo_Tnaosi=aQX8sGKBh01zG2aj"  
[X Link](https://x.com/zaelefty/status/2001672586422272247)  2025-12-18T15:15Z 52K followers, [----] engagements


"BREAKING: RFK Jr announces moves to ban sex-rejecting procedures (so called gender affirming care) for minors nationwide. This could become one of the biggest wins for the protection of children in years"  
[X Link](https://x.com/zaelefty/status/2001715814529990965)  2025-12-18T18:06Z 52K followers, [----] engagements


""The paper claims that strong opposition to FGM is motivated by Western-centered morality that reinforces colonial power. But these practices are barbaric. The evil of injuring a childs body does not depend on geography race or historical power." https://read.theparadoxinstitute.org/p/academics-defend-fgm-in-the-journal https://read.theparadoxinstitute.org/p/academics-defend-fgm-in-the-journal"  
[X Link](https://x.com/zaelefty/status/2002431399517946106)  2025-12-20T17:30Z 52.1K followers, [----] engagements


"A biological anthropologist @MorphoTime just claimed on @joerogan that human sex change is possible because of a disorder where "females turn into males at puberty." He makes [--] false claims. Let's break it down. [--]. He first claims "We all start out as females." No we all start genetically sexed and physically undifferentiated with bipotential gonads the primordial genital ducts for both sexes and a cloaca (Wolpert et al 2019). Note these are not female gonads or genitalia. Around the 6th week genetics differentiate our neutral gonads into testes OR ovaries and then genetics and hormonal"  
[X Link](https://x.com/zaelefty/status/2002879336005669199)  2025-12-21T23:10Z 52.1K followers, 233.1K engagements


"For more on 5-ARD and other sex development disorders my new book explores [--] DSDs using clear diagrams and accessible commentary that combines genetics and dev bio with real-world clinical practice. Order at 🔗 http://sexdevelopmenthandbook.com http://sexdevelopmenthandbook.com"  
[X Link](https://x.com/zaelefty/status/2002880790741606603)  2025-12-21T23:16Z 52K followers, 10.1K engagements


"@B_FettDaVet @MorphoTime @joerogan @grok 5-ARD is variable in its rate. The higher incidence is found in isolated communities with high rates of inbreeding such as areas in the Dominican Republic where rates can be as high as [--] in [--]. In the U.S. it is extremely rare"  
[X Link](https://x.com/zaelefty/status/2002939900916871621)  2025-12-22T03:10Z 52.1K followers, [----] engagements


"@MorphoTime @joerogan Not a troll. Its a detailed scientific rebuttal of false claims about a disorder using in-text scientific papers. The goal is to help educate others and stop the spread of misinformation about people with disorders of sex development whose care is often harmed by false info"  
[X Link](https://x.com/zaelefty/status/2003183227817832762)  2025-12-22T19:17Z 52K followers, [----] engagements


"@TheRHNeutrino @MorphoTime @joerogan Check out our animated video on this which explores the science in detail :) Jurassic Park helped popularize the myth that we all begin female. https://youtu.be/fz7NQDfa4eUsi=M7oiIW36kxRW0mqU https://youtu.be/fz7NQDfa4eUsi=M7oiIW36kxRW0mqU"  
[X Link](https://x.com/zaelefty/status/2003196565427749174)  2025-12-22T20:10Z 52.1K followers, [---] engagements


"Our official rebuttal to the famous Scientific American article that uses the complexities of sex determination and the diversity of sex differences to argue that sex is not binary. Subscribe for two articles a week straight to your inbox. https://read.theparadoxinstitute.org/p/a-response-to-sciams-stop-using-phony https://read.theparadoxinstitute.org/p/a-response-to-sciams-stop-using-phony"  
[X Link](https://x.com/zaelefty/status/2003220357868847256)  2025-12-22T21:45Z 52K followers, [---] engagements


"Our official rebuttal to the famous Scientific American article "Stop Using Phony Science to Justify Transphobia." Subscribe for two articles a week straight to your inbox. https://read.theparadoxinstitute.org/p/a-response-to-sciams-stop-using-phony https://read.theparadoxinstitute.org/p/a-response-to-sciams-stop-using-phony"  
[X Link](https://x.com/zaelefty/status/2003220633619190039)  2025-12-22T21:46Z 52K followers, [----] engagements


".@MorphoTime and @joerogan this educational animation debunks the "we all begin female" myth and explains where it originated. It uses recent developmental biology and genetics research found in textbooks and scientific papers. Have a watch and let me know what you think"  
[X Link](https://x.com/zaelefty/status/2003490363005370670)  2025-12-23T15:38Z 52.1K followers, 11.5K engagements


"@CommanderKalyan @MorphoTime @joerogan Woohoo thats my goal Check out my charts for the steps of sex development for typical males and females and many disorders of sex development. https://theparadoxinstitute.org/read/sex-development-charts https://theparadoxinstitute.org/read/sex-development-charts"  
[X Link](https://x.com/zaelefty/status/2003856569906368696)  2025-12-24T15:53Z 52.1K followers, [---] engagements


"@beebearninja No they apply to all regions. If on Amazon be sure to buy it from your region-specific Amazon site"  
[X Link](https://x.com/zaelefty/status/2004357166665539620)  2025-12-26T01:02Z 52.1K followers, [--] engagements


"Anthropologist @MorphoTime claimed on @joerogan that humans can change sex through a disorder in which females turn into males at puberty. Let's explore the claims with scientific evidence in our full video response. @RobSchneider"  
[X Link](https://x.com/zaelefty/status/2004587735198412874)  2025-12-26T16:18Z 52.1K followers, 17.2K engagements


"We are looking for viral claims about biology that are completely false or misleading to debunk every week in our new Paradox Proofs series. If you see a viral science claim you want audited send it to us using our contact form here https://theparadoxinstitute.org/contact https://theparadoxinstitute.org/contact"  
[X Link](https://x.com/zaelefty/status/2004774960418677014)  2025-12-27T04:42Z 52.1K followers, [----] engagements


"My video response to anthropologist Michael Masters' false claims about 5-ARD on Joe Rogan is now an article on our Paradox substack Subscribe there for exclusive articles every week on the biology of sex sent straight to your inbox. https://read.theparadoxinstitute.org/p/joe-rogan-guest-claims-humans-can https://read.theparadoxinstitute.org/p/joe-rogan-guest-claims-humans-can"  
[X Link](https://x.com/zaelefty/status/2005357849283870911)  2025-12-28T19:19Z 52.1K followers, [----] engagements


"It is a mistake to believe that by taking down one head of gender ideology you will achieve success. You must strike at the foundation: the heart of the hydra. A piece by @PTElephant. Subscribe for new articles sent straight to your inbox every week https://read.theparadoxinstitute.org/p/trans-ideology-the-modern-hydra-f19 https://read.theparadoxinstitute.org/p/trans-ideology-the-modern-hydra-f19"  
[X Link](https://x.com/zaelefty/status/2005787641116332338)  2025-12-29T23:46Z 52.1K followers, 10.5K engagements


"Today is the last day to buy the Paradox Institute's bestselling biology books at 20-30% off The Sex Development Handbook teaches how males and females develop in the womb along with [--] disorders of sex development in elegant diagrams and accessible commentary for a wide audience. 🔗 It All Begins With Two is a beautifully illustrated age-appropriate exploration for kids of how new life begins and why there are only two sexes across humans other animals and plants. 🔗 Binary tackles [--] sex spectrum arguments and debunks them with evidence from evolutionary and developmental biology. 🔗"  
[X Link](https://x.com/zaelefty/status/2006427087058399326)  2025-12-31T18:07Z 52.1K followers, [----] engagements


"Today I discovered that Paradox Institute is run by an archaeologist and that our content is created to confuse the elderly 👵"  
[X Link](https://x.com/zaelefty/status/2006782714868019544)  2026-01-01T17:40Z 52.1K followers, [----] engagements


"People have asked me how I know so much about biology without receiving a degree. Its called [--] years of studying the scientific literature writing about it and consulting with experts. You can just learn things Knowledge is not confined to those who can pay an institution tens of thousands of dollars to teach them. Now I would love to get a formal biology degree when I am able to as it would deepen and enhance my knowledge even more but degrees are not something that are necessary to understand and learn truths about the world. Thinking otherwise is rather elitist and incorrect"  
[X Link](https://x.com/zaelefty/status/2006786359990657251)  2026-01-01T17:55Z 52.1K followers, 13.9K engagements


"We do not all start female. We begin genetically sexed and physically undifferentiated before genetics guide us down either male or female path. Learn why in just [--] minutes as I walk you through the scientific literature"  
[X Link](https://x.com/zaelefty/status/2006915461523583410)  2026-01-02T02:28Z 52.1K followers, 31.3K engagements


"No what determines sex is a technical dev bio phrase that describes the trigger that places the embryo on the male or female pathway. In mammals including humans this is determined by genetics. In the male embryo whose sex has been determined by genetics differentiating the gonads into testes testicular hormones activate gene pathways that differentiate the male genital ducts. In the female embryo whose sex has been determined by genetics differentiating the gonad into ovaries the lack of male hormones from the ovaries activates a different set of gene networks that form the females genital"  
[X Link](https://x.com/zaelefty/status/2007159049851191788)  2026-01-02T18:36Z 52.1K followers, [---] engagements


"North Carolina now recognizes only two sexes and defines sex with respect to biology not gender identity. An incredible win for our home state"  
[X Link](https://x.com/zaelefty/status/2008744153312858303)  2026-01-07T03:35Z 52.2K followers, 81K engagements


"You cannot change your sex even if you are fully transitioned. All that means is that you have mutilated your sexed body with hormones and surgery. You have not transformed into the opposite sex which would require the complete switch of the entire reproductive system. @zaelefty Isn't that unfair to fully transitioned trans women As far as science allowed of course. @zaelefty Isn't that unfair to fully transitioned trans women As far as science allowed of course"  
[X Link](https://x.com/zaelefty/status/2008947482416357777)  2026-01-07T17:02Z 52.1K followers, 52.9K engagements


"Anthropologists can determine sex through the skeleton with close to 100% accuracy. Learn what they look for in this episode of Paradox Proofs"  
[X Link](https://x.com/zaelefty/status/2009632849994149888)  2026-01-09T14:26Z 52.1K followers, [----] engagements


"The Supreme Court is hearing arguments today on the state bans on males in female sports. See our animated video on the practical scientific process for ensuring no males can compete in the female category"  
[X Link](https://x.com/zaelefty/status/2011102527568425455)  2026-01-13T15:46Z 52.2K followers, 10.9K engagements


"It does not matter whether a male's sports performance advantages are less than equal to or greater than the female average. Males have no right to compete in female categories"  
[X Link](https://x.com/zaelefty/status/2011127277925580873)  2026-01-13T17:24Z 52.1K followers, 106.1K engagements


"The argument that males who identify as trans are being banned from sports needs to stop. We are all tired of hearing it especially from our own side. Please stop saying this. Males of any identification can play on the MALE sports teams. No one is stopping them. Justice Kavanaugh: "I hate hate that a kid who wants to play sports might not be able to play sports. Hate that. But it's kind of a zero sum game for a lot of teams. Someone who tries out and makes it who is a transgender girl.will bump someone else." https://t.co/aX32ZnzPiH Justice Kavanaugh: "I hate hate that a kid who wants to"  
[X Link](https://x.com/zaelefty/status/2011278910731010292)  2026-01-14T03:27Z 52.1K followers, 22.4K engagements


"Watch as a supposed Dr squirms to answer the question Can men get pregnant"  
[X Link](https://x.com/zaelefty/status/2011542081467191725)  2026-01-14T20:52Z 52.1K followers, [----] engagements


"The question was "Can men get pregnant" Women with Swyer Syndrome are not men. Due to loss of male-sex determining genes the XY fetus develops down the female pathway: oviducts uterus cervix vagina vulva etc. The only thing they are missing are differentiated gonads. Hmm this person with XY chromosomes did get pregnant and gave birth. Thanks for coming to this TED talk. https://t.co/tGM2upLa8H Hmm this person with XY chromosomes did get pregnant and gave birth. Thanks for coming to this TED talk. https://t.co/tGM2upLa8H"  
[X Link](https://x.com/zaelefty/status/2011832579213648152)  2026-01-15T16:07Z 52.2K followers, 28K engagements


"An impressive meta-analysis of 300000+ children by @JamesLNuzzo shows that male newborns have a 13% higher grip strength than female newborns. At puberty the advantage rises to around 36%"  
[X Link](https://x.com/zaelefty/status/2011834283233575220)  2026-01-15T16:14Z 52.2K followers, [----] engagements


"Women are not small men. Women are not men with low testosterone. Women are not underdeveloped men. Women are adult human females with their own unique and profound anatomy and physiology. Men and women are not derived from the other. They are their own unique categories"  
[X Link](https://x.com/zaelefty/status/2012037375556534632)  2026-01-16T05:41Z 52.1K followers, 50.4K engagements


"Trump signs the executive order banning males from female sports protecting women and girls rights to fair and safe competition"  
[X Link](https://x.com/anyuser/status/1887277951944720878)  2025-02-05T23:11Z 52.1K followers, 1.4M engagements


"It looks like pricing for AU is not showing up on Amazon's KDP system. Not sure why. It might be related to not being 100% supported with the 8.5x11 hardcover binding in the AU market. Let me know what Binary looks like as well. That should be apply just fine to AU as the pricing is showing up. But with the Handbook what about trying to order through US shipped to AU Would that be cheaper"  
[X Link](https://x.com/zaelefty/status/2004367852787339588)  2025-12-26T01:45Z 52.1K followers, [--] engagements


".@Scott_Wiener claims that it is hypocritical to ban sex-rejecting procedures for trans-identified teens while keeping the same ones legal for "non-trans" teens. But the medical practices legal for "non-trans teens" are not the same procedures at all. [--]. Puberty blockers Puberty blockers used for "non-trans teens" are only used for precocious puberty at an early window in development and for a brief time period to help sex-specific puberty occur at a more healthy time. This is in contrast to their use in sex-rejecting procedures which are used to permanently halt the sex-specific puberty to"  
[X Link](https://x.com/anyuser/status/2005116115173667034)  2025-12-28T03:18Z 52.1K followers, 12.6K engagements


""Our society used to say a girl who plays with male-typical toys was a tomboy. Now we say she is a boy that she should become a boy. But why Only if you believe that gender expression is the indicator of your true sex." Watch the full video at: https://www.theparadoxinstitute.com/pi.html https://www.theparadoxinstitute.com/pi.html"  
[X Link](https://x.com/anyuser/status/1247328437024501761)  2020-04-07T01:00Z 52.1K followers, [---] engagements


"Nipples are a common trait shared between males and females. They are not exclusive to one sex. Making the jump from both sexes have X to males having X must mean they begin as females does not logically follow. @zaelefty @MelissatheTERF Its true. That is why males have nipples. The body starts building as XX but the Y is simply incomplete X chromosome. Thats why males stillbirth rates are much higher . @zaelefty @MelissatheTERF Its true. That is why males have nipples. The body starts building as XX but the Y is simply incomplete X chromosome. Thats why males stillbirth rates are much higher "  
[X Link](https://x.com/zaelefty/status/2012395740832653606)  2026-01-17T05:25Z 52.1K followers, [----] engagements


"RT @JanuaryDoNoHarm: How many children will be gender trafficked away from their loving parents This case sounds eerily similar to a case"  
[X Link](https://x.com/zaelefty/status/2017738869823676606)  2026-01-31T23:16Z 52.1K followers, [--] engagements


"When I released Binary two years ago the goal was to explain how sex is universally defined across species and debunk common sex spectrum arguments. It became a #1 bestseller in Biology. Now my latest book The Sex Development Handbook maps how sex develops in humans--from typical development to more than [--] DSDs--with each spread featuring a color-coded diagram and engaging commentary. Recommended as an essential read for high schools colleges and graduate schools the handbook shows each human even those with rare disorders develops as a male or female integrating real-world clinical practice"  
[X Link](https://x.com/zaelefty/status/1988073251503849673)  2025-11-11T02:36Z 52.1K followers, 29.8K engagements


"No we do not all start female. We start genetically sexed and physically undifferentiated. For the first [--] weeks both sexes begin with physically indifferent bipotential gonads and a cloaca before genetics differentiate that anatomy down either the male or female path. @zaelefty @MelissatheTERF Its true. That is why males have nipples. The body starts building as XX but the Y is simply incomplete X chromosome. Thats why males stillbirth rates are much higher . @zaelefty @MelissatheTERF Its true. That is why males have nipples. The body starts building as XX but the Y is simply incomplete X"  
[X Link](https://x.com/zaelefty/status/2012373610724196559)  2026-01-17T03:57Z 52.1K followers, [----] engagements


"See my summary of the scientific literature debunking this common claim. https://youtu.be/aHtqzfp1lpMsi=EA5sh9K-rtu2uJTO https://youtu.be/aHtqzfp1lpMsi=EA5sh9K-rtu2uJTO"  
[X Link](https://x.com/zaelefty/status/2012381560956227745)  2026-01-17T04:28Z 52.1K followers, [----] engagements


"There is a categorical difference between taking supplemental sex hormones to support the healthy development of ones sex vs taking cross-sex hormones to undermine and reject ones sexed body. No hypocrisy at all. If you support this stuff but are against trans people taking HRT youre a huge hypocrite btw https://t.co/W9GAJ3letn If you support this stuff but are against trans people taking HRT youre a huge hypocrite btw https://t.co/W9GAJ3letn"  
[X Link](https://x.com/zaelefty/status/2012707617500443030)  2026-01-18T02:04Z 52.1K followers, 44.9K engagements


"The "trans" kid is not biological. It is something manufactured to validate adult delusions. In this piece @PTElephant explores how deluded adults take advantage of children's development. https://read.theparadoxinstitute.org/p/the-myth-of-the-trans-kid https://read.theparadoxinstitute.org/p/the-myth-of-the-trans-kid"  
[X Link](https://x.com/zaelefty/status/2012985380832686488)  2026-01-18T20:28Z 52.1K followers, 13.1K engagements


"Trans activists claim defining sex erases trans people. Im not sure how that would work. First theyll have to explain the mechanism behind how classifying a biological reality erases people. Second the term trans only has meaning relative to sex. If sex didnt exist the social category of trans wouldnt exist either. So theyre rather undermining their own point"  
[X Link](https://x.com/zaelefty/status/2013150810532712688)  2026-01-19T07:25Z 52.1K followers, 21.9K engagements


"See the full transcript scientific sources and YouTube link here. https://theparadoxinstitute.org/videos/do-we-all-begin-female https://theparadoxinstitute.org/videos/do-we-all-begin-female"  
[X Link](https://x.com/zaelefty/status/2013939145425506691)  2026-01-21T11:38Z 52.1K followers, [----] engagements


"Being male is a development pathway around a specific gamete type. It is not a karyotype. So losing the Y chromosome does nothing useful for trans arguments. If our sex determination system changed overnight wed still produce males. And they would still be defined as the development path organized around sperm. @IanCopeland5 The Y chromosome isn't imperative for male survival evolutionarily. If Y chromosomes arent a reliable determinant of male survival then I feel like this basically debunks using it as an argument against trans people. @IanCopeland5 The Y chromosome isn't imperative for"  
[X Link](https://x.com/zaelefty/status/2016015837623169454)  2026-01-27T05:10Z 52.1K followers, [----] engagements


"RT @BillboardChris: Transgender ideology is pushed by very dark twisted and evil people. In a graphic email sent to Epstein in 2018-year"  
[X Link](https://x.com/zaelefty/status/2018331011512164672)  2026-02-02T14:29Z 52.1K followers, [---] engagements

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