On August 9, 2024, Algerian boxer Imane Khelif won the gold medal in women’s boxing at the Paris Olympics. The celebration was clouded, though, by allegations that Khelif wasn’t a woman, but a man boxing against women. If true, at bare minimum, this was unfair. At worst, it was assault. Those defending the boxer countered that since Khelif had no male genitals, the athlete was, therefore, a woman.
Khelif’s sex was a matter of controversy for weeks leading up to and following the gold medal match. The boxer’s medical records were private, however, making a definitive public assessment impossible at the time. Misinformation on sex and sexual development coming from all quarters added to the confusion.
For the first time in history, a precise answer to the question “What is a woman?” is beyond the reach of many otherwise intelligent and educated people. Even U.S. Supreme Court Justice Ketanji Brown Jackson balked when asked during her nomination hearing to provide a definition for the word “woman.” “I’m not a biologist,” she said,[1] as if biologists were the only ones qualified to distinguish between the sexes.
Yet even some scientists squirm when pressed for a definition. The commonsense definition of “woman” as an adult human female has the consequence of disqualifying biological males who “identify” as females. In the current political climate, this kind of candor ends careers.
The question “What is a woman?” raises other questions. What is a man? Are those the only choices—male or female? If so, why? What distinguishes a male from a female when there are ambiguities in sexual anatomy?
In spite of the current confusion, clear answers to these questions are not difficult to come by. Indeed, the technical criteria have been well known for a long time. The only ones truly confused are modern gender theory advocates and those who listen to them.
How Many Sexes?
Up until the last few beats of human history, there’s been no confusion on the divisions between the sexes, for good reason. The distinctions were obvious. For Homo sapiens, sex is binary. People are born—indeed, conceived—either male or female.
Not so today. Now some biologists and psychologists say there are more than two sexes—even a spectrum of sexual variations often referred to as “sexual identities.” Pop publications push this new narrative. USA Today, for example, tweeted that there are “three different types of sexes.”[2] Egale, a Canadian LGBT advocacy group, uses a clever rhyme to teach kids that, when it comes to men and women, “You can be both or a mix of the two, or you can be neither if that’s what suits you.”[3]
To most people, however, these new claims are at odds with common sense. Still, many wonder if they’re missing something. Have there been new discoveries disqualifying what we thought we knew about human sexuality? The answer is no.
Though pockets of our culture are confused about fundamental human nature, there’s no excuse for Christians to be confused. Our Maker confirms through special revelation—Scripture—what we already know from observational common sense: God made humans male and female. Full stop.
Here is the biblical record of God’s sexual design for humanity: “God created man in His own image, in the image of God He created him; male and female He created them” (Gen. 1:27).
When God fashioned the human race, he created two sexes and only two sexes. Jesus confirms this design when, in Matthew 19:4, he cites God’s created order described in Genesis: “Have you not read that He who created them from the beginning made them male and female?” According to both Jesus and Genesis, our Maker made only males and females. Scripture never hints at the possibility of any other variation.[4] That’s why God’s people have spoken with one voice on this for thousands of years.
We have confirmation of God’s intention for the created order through another source. Scientific research[5] also verifies the fact that human sexuality is binary, either male or female. During my training as a physical therapist in the 1990s, my professors taught that human sexuality is binary. They weren’t Christians—in fact, one was an outspoken atheist—yet they still understood what nature had made obvious.
Characteristically, males have one X and one Y chromosome (XY), while females have two X chromosomes (XX). The Y chromosome contains a specific gene, the SRY gene or “male-determining” gene, that triggers a cascade of genetic events in the human embryo that cause the development of a male body with a penis and testes. Without the SRY gene, the embryo develops into a female body with a vagina and ovaries. This relationship between genes and sex has been understood since its discovery over 100 years ago by biologist Nettie Stevens in 1905.[6]
That human bodies develop either testes or ovaries is the key to understanding why there are only two sexes. There are only two sexes because there are only two kinds of reproductive cells (gametes) a human can produce. Human bodies are designed to produce either sperm or eggs. There is no other possible gamete—no intermediate “spegg” combination of sperm and egg—that a human body can produce. If there were a third gamete, there would be a third sex. But there isn’t. There are, therefore, only two sexes.
Granted, some human bodies, regardless of chromosomal makeup, are incapable of producing sperm or eggs. This shortcoming, however, doesn’t change our basic understanding of human physiology. For example, human beings walk on two legs; they’re bipedal by nature. However, if someone with a congenital defect is born with only one leg, or if someone loses a leg through an accident, we don’t conclude that humans manifest a spectrum of forms of human locomotion rather than being bipedal. No, humans are still bipedal by nature despite the abnormalities.
In the same way, when people are born with sexual anatomical anomalies that interfere with or prohibit the natural development of male or female sex organs, that doesn’t mean they represent an entirely different sex. The sexual binary classification is not falsified because of biological irregularities.
Intersex
Gender ideology advocates disagree. Not every person can be easily classified as male or female based on chromosomes, they point out, since not all males are XY and not all females are XX. Some people are born intersex, a condition that covers a broad range of chromosomal or anatomical variations that affect a person’s external sex characteristics. A number of variants fall under this heading.
For example, although males typically have XY chromosomes, it’s possible for a male to have XX chromosomes. In de la Chapelle syndrome, the SRY gene is translocated to the X chromosome. The result is a human embryo with XX chromosomes where the male-determining gene triggers the body to develop a penis, testes, and, eventually, sperm. It’s also possible for a female to have XY chromosomes. In Swyer syndrome, a female has XY chromosomes, but a mutation deletes the SRY gene from the Y chromosome. With no male-determining gene directing sexual development, the embryo with XY chromosomes develops a vagina, ovaries, and eggs and is, therefore, female.
Some males are born with XXY chromosomes (Klinefelter syndrome). Some females are born with only one X chromosome (Turner syndrome). Some women over-produce or under-produce sex-related hormones, while others might be born without a vagina (vaginal agenesis). The list goes on, prompting gender theory advocates to conclude that sex is not binary since not all people fit neatly into male or female categories with XY or XX chromosomes or either a penis or a vagina.
Even so, neither chromosomal variations nor the existence of intersex people nullifies the sexual binary or our ability to categorize people as either male or female. Rather, those born with atypical genetics or biology represent variations within the sexual binary categories of male and female, not a negation of them.
Agreed, in rare cases when a child is born, it’s not immediately obvious whether the baby is male or female. According to a 2018 study researching intersex conditions, only one in 2,000 births to one in 4,500 births produces a child with ambiguous genitalia.[7] In rare conditions where a child’s sex is unclear at birth, it can often be discovered with genetic testing, ultrasound, and other evaluative tools. Note, though, that these methods discover the child’s actual sex that was merely obscured during the initial observations. There is no inherent sexual uncertainty.[8]
Most intersex people appear and function as either male or female. Furthermore, even though some people are intersex, that does not mean they’re transgender. Even the Intersex Society of North America (ISNA) admits that “the vast majority of people with intersex conditions identify as male or female rather than transgender or transsexual.”[9]
Here’s a key takeaway: chromosomes do not determine sex. Sex determination is the unique role of the SRY gene regardless of the combination of chromosomes. In fact, as noted, people can be born with a myriad of chromosomal variations, such as XXY, XXXY, XYY, XYYY, XXYY, etc., yet none of these conditions negate the sexual binary. They don’t indicate a third sex, a spectrum of sexes, or an “in-between” sex. Chromosomal differences simply represent variations within the two categories of male and female.
What Is a Woman?
The previous discussion on how we know there are only two sexes also helps answer another question: What is a woman? The repetition of the recent “trans women are women” mantra has created unnecessary confusion.
Numerous definitions for “woman” have surfaced over the last few years. These definitions fall into one of three categories. They are either circular, absurd, or sound.
First, some definitions of “woman” are circular or tautological.[10] This mistake occurs when the proposed definition of a word includes in it the very word it’s trying to define. For example, defining nuclear power as energy derived from a nuclear source is unhelpful because the word being defined, “nuclear,” is used in the definition. The attempt, then, is tautological: Nuclear energy is energy that is nuclear.
When transgender advocates define a woman as “anyone who identifies as a woman,” they falter in the same way. Using the word “woman” in the definition of the word renders the definition circular. The meaning of a word cannot be clarified simply by repeating the word (“a woman is a woman”). More is required.
Second, some definitions of “woman” are simply absurd. The Cambridge Dictionary recently amended its definition of “woman” to include “an adult who lives and identifies as female though they may have been said to have a different sex at birth.”[11] Cambridge merely replaced the word “woman” with the word “female.”
This attempt skirts the circularity problem, but it falls into a different ditch. The word “female” refers to biology. A biological female is a person who typically has XX chromosomes and possesses reproductive organs—ovaries and a uterus—that make child-bearing possible. What does it mean, then, for a man with XY chromosomes who possesses a penis and testes to live and identify as a someone who possesses ovaries and a uterus? His belief is delusion, pure and simple.
Note that the 69-year-old Dutch TV personality Emile Ratelband decided to identify as a 49-year-old and demanded that the courts change his legal age.[12] Of course, the notion is absurd since no amount of sincerity, hormonal injections, or surgical intervention can change the calendar. Ratelband can make cosmetic changes to his body that make him look younger, but he’ll never be younger. That’s because age is a biological reality that can’t be altered. In the same way, a person’s sex is an immutable, unalterable biological reality. A man can cosmetically look more feminine, but he’ll never become female. For all the contrary cultural bluster, sex change is biologically impossible.
The other problem with the modified Cambridge definition of “woman” is that, on their definition, someone could have had “a different sex at birth” from the one they have as an adult. Thus, the word “woman” could then be applied to someone who was once the opposite of a woman. That’s similar to saying that parallel lines can be redefined as perpendicular or that married men can be redefined as bachelors. This is borderline incoherent.
Third, some definitions of “woman” are sound. In the prior eras of cultural—and biological—clarity, the definition of “woman” was uncontroversial. A woman was an adult human female.
Though this definition is serviceable for our needs since it’s fundamentally correct, some qualifications are in order. Although intersex individuals don’t nullify the sexual binary, a precise definition of “woman” needs to capture the wide range of physiological variations that occur with women.
Here are the definitions I’ve formulated that accurately define “woman” and “man.” They are not arbitrary, but rather fit with our commonsense understanding of human beings by focusing on the unique, empirically observed biological functions of each sex. A woman is an adult human being whose body is organized around the two related functions of 1) the production, storage, and delivery of eggs, and 2) the gestation of another human being. A man is an adult human being whose body is organized around the production, storage, and delivery of sperm.
Notice the importance of the phrase “organized around.” Yes, a particular woman might have atypical genetics or sexual anatomy, but that doesn’t nullify her standing as a true woman. Even if one or more of her reproductive organs is malformed, missing, or has been removed (e.g., through hysterectomy), her body is still “organized around” the use of eggs and the gestation of another human being. The same principle applies for biological men.
How We Know Who Is Male and Who Is Female
Is there a reliable, scientific method to determine if someone is male or female? Yes, there is. Established scientific criteria providing definitive answers to this question have been in place for over 100 years. Only since the recent rise of transgender ideology has there been any substantial pushback on these principles.
Three empirically based methods determine whether a person is male or female.
First, a person’s genitalia are an indicator of that person’s sex. Males have a penis and testes, while females have a vagina and ovaries. A visual inspection of someone’s anatomy (or an ultrasound to detect ovaries or internal testes) is all that’s needed to settle the matter, in most cases. People with misshapen or malformed genitals, however, may need a second level of assessment.
A person’s chromosomes can also be an indicator of that person’s sex. The presence of XY chromosomes typically specifies male sex, and the presence of XX chromosomes typically specifies female sex. In rare instances, though, chromosomes are not a definitive marker. That’s why it’s scientifically incorrect—and strategically unwise—to defend binary sexuality in humans by simply appealing to a chromosomal standard, XY for male and XX for female.
Chromosomes may be an effective indicator of sex, but they do not determine sex. As mentioned above, sex is determined by a gene—the SRY gene, specifically. Because a gene governs sexual development, genetic makeup is the third and most precise way to determine whether a person is male or female.[13]
A person’s genetic makeup is fixed the moment sperm and egg combine. Therefore, humans are “sexed” at conception. Sex is never “assigned” at birth. It’s merely discovered at birth—or, frequently, weeks before birth through ultrasound.
Keep in mind that there’s a difference between what determines sex and what defines sex. Genes determine sex, triggering and regulating the pathways that guide a human embryo to develop male or female sexual structures. Sex is defined by those sexual structures themselves—specifically, the type of reproductive cells (gametes) a body is designed to produce, sperm for males and eggs for females.
Imane Khelif: Male or a Female? Man or Woman?
Is Imane Khelif male or female? At the time of the Paris Olympics, it was difficult to give a definitive answer since the athlete’s genetic information was not public at the time. We did know, however, that Khelif was disqualified from competing as a female by the International Boxing Association (IBA) in 2023. The IBA requires that a fighter possess XX chromosomes to qualify as female. The disqualification suggested that Khelif had the XY chromosomes of a male. In addition, Khelif’s trainer, Georges Cazorla, told the French magazine Le Point that Khelif had a high testosterone level.[14]
Given this limited information, it appeared that Khelif was intersex. The likelihood that Khelif had XY chromosomes, high levels of testosterone, and genitals that appeared female at birth narrowed down the possible intersex conditions Khelif could have: either partial androgen insensitivity syndrome (PAIS) or 5-ARD.
A recent report has confirmed that Khelif has XY chromosomes, testicles, and the intersex condition 5-ARD,[15] which affects XY chromosomal males. 5-ARD is a genetic mutation that prevents the conversion of testosterone into a chemical that masculinizes the male genitalia. As a result, the penis and scrotum don’t form and the testes don’t descend, though testes still exist and remain in the abdomen. Outwardly, the genitals of people with 5-ARD look more female since they don’t have a penis or external testes. Their internal testes still produce testosterone, though, which surges during puberty, masculinizing their skeletal, muscular, and cardiovascular systems.
Imane Khelif, then, is a man. Though he lacks external male genitalia, Khelif still has all the athletic advantages of other men. It’s no surprise, then, that people are upset. He’s being allowed to compete in a sport in which one person punches another—in this case, a man punching a woman.
What We Learned and What We Do About It
Our careful scientific assessment of basic human sexual physiology—an evaluation completely consistent with our commonsense understanding of human sexual development—clears up the confusion that many experience regarding sex and gender. Here are the important takeaways:
- Sex for Homo sapiens is binary. Humans are either male or female.
- A woman is an adult human female. A man is an adult human male.
- Males and females are distinguished by the reproductive role their bodies are organized around, with males producing sperm and females producing eggs, their union producing children.
- Sex is defined by the kinds of gametes a human is naturally equipped to produce—sperm for men and eggs for women.
- Sex is determined by genetics, not by chromosomal combination. Humans with a properly functioning SRY gene are male. Those lacking a properly functioning SRY gene are female.
- Sex is discovered by 1) observation, 2) through examining the chromosomes or, most reliably, by 3) genetic analysis.
- Neither chromosomal variations like XXX, XXY, XYY, etc., nor the sexual ambiguity of those who are intersex indicates a third sex, an in-between sex, or a spectrum of sexes. They only indicate variations within the binary categories of male and female determined by the presence or absence of an active SRY gene.
- Though determining a person’s sex might sometimes be complicated, even so, human sex is still binary because every human either has an active SRY gene or does not have an active SRY gene.
Given what we’ve learned, how should we treat someone who is intersex? The appropriate response is to treat them with truth, love, and compassion—just like everyone else.
Those with intersex conditions are made in the image of God like the rest of us. Each is intrinsically valuable and deserves to be treated with the dignity and respect appropriate for all human beings. There’s no place for dehumanizing talk or degrading insults toward Khelif or any others because they’re intersex. While it’s appropriate to argue for fair and safe rules in sports, it’s never appropriate to dehumanize any of God’s image-bearers, even if you strongly disagree with them.
Though the culture is confused, there is no reason for Christians to be confused. Though the culture advances politically or ideologically driven opinions about Khelif’s sex, followers of Christ can stand on scientifically established principles and make their case in a precise, persuasive, and gracious manner. There’s no need to act like bullies. There’s no need to call names.
I like the way former ambassador Alan Keyes put it. He said we should “move forward...not to calculate the victory or to fear the defeat, but to do our duty. And to leave the rest in his almighty hands.”[16]
It’s not our responsibility to convince everyone of our ideas. It’s our responsibility to be faithful to the truth, present our case as best we can, and then leave the results up to God.
[1] Alia E. Dastagir, “Marsha Blackburn asked Ketanji Brown Jackson to define ‘woman.’ Science says there’s no simple answer,” USA Today, March 24, 2022, https://www.usatoday.com/story/life/health-wellness/2022/03/24/marsha-blackburn-asked-ketanji-jackson-define-woman-science/7152439001/.
[2] USA Today, X, May 30, 2021, https://x.com/USATODAY/status/1399123200861167620.
[3] Eva Kurilova, “From Gay Rights to Trans Wrongs: Egale’s Lucrative Transition,” Gender Dissent, October 11, 2023, https://www.genderdissent.com/post/from-gay-rights-to-trans-wrongs-egale-s-lucrative-transition.
[4] See Alan Shlemon, “Does the Bible Limit Gender to Just Male and Female?” Stand to Reason, September 2, 2021, https://www.str.org/w/does-the-bible-limit-gender-to-just-male-and-female-.
[5] I use the phrase “scientific research” to identify those things we are capable of knowing through a careful look at God’s created order. Theologians call this “natural revelation.”
[6] Sarah B. Carey, Laramie Akozbek, and Alex Harkess, “The contributions of Nettie Stevens to the field of sex chromosome biology,” Philosophical Transactions B (March 21, 2022): https://doi.org/10.1098/rstb.2021.0215.
[7] Selma Feldman Witchel, “Disorders of sex development,” Best Practices & Research Clinical Obstetrics & Gynaecology 48 (April 2018): 90–102, https://doi.org/10.1016/j.bpobgyn.2017.11.005.
[8] To repeat for clarity’s sake, the “intersex” condition does not denote a discreet sexual category different from either male or female. Rather, it’s a condition afflicting both males and females that occasionally—but not typically—makes their true sex more difficult to determine.
[9] “What’s the difference between being transgender or transsexual and having an intersex condition?” Intersex Society of North America, https://isna.org/faq/transgender.
[10] A tautology in this sense means an unhelpful repetition.
[11] Cambridge Dictionary, s.v. “woman,” accessed December 1, 2024, https://dictionary.cambridge.org/us/dictionary/english/woman.
[12] “Emile Ratelband, 69, told he cannot legally change his age,” BBC, December 3, 2018, https://www.bbc.com/news/world-europe-46425774.
[13] A qualification is in order. In exceedingly rare cases, a person has the SRY gene, but due to mutations or other problems affecting the genetic pathway, the person still develops as a female. In that situation, since the SRY gene is present but not biologically active, it does not function as a male-determining gene. In either case, the most definitive scientific way to determine sex is by examining genetic pathways.
[14] Georges Cazorla, “2024 Olympics: Imane Khelif was devastated to discover out of the blue that she might not be a girl!” interview by Beatrice Parrino, Le Point, August, 14, 2024, https://www.lepoint.fr/monde/2024-olympics-imane-khelif-was-devastated-to-discover-out-of-the-blue-that-she-might-not-be-a-girl-14-08-2024-2567924_24.php.
[15] Anna Slatz, “Algerian Boxer Imane Khelif Has XY Chromosomes and ‘Testicles’: French-Algerian Medical Report Admits,” Reduxx, November 4, 2024, https://reduxx.info/algerian-boxer-imane-khelif-has-xy-chromosomes-and-testicles-french-algerian-medical-report-admits/.
[16] Alan Keyes, “Keyes Campaign Speech,” C-SPAN, February 27, 2000, video, https://www.c-span.org/video/?155702-1/keyes-campaign-speech.