Our sex is written in our genes, can be clearly determined for each person and does not change throughout life. On the one hand is the woman, on the other - the man - the princess and the knight. And in between? No man's land.
Many think this way. Among them is US President Donald Trump, who, upon taking office in his new term, announced that there are only two sexes. A similar opinion was shared by the leader of the German Christian Democrats, Friedrich Merz, during his debate against the current Chancellor Olaf Scholz.
People who claim that there are two sexes rely on science, or more specifically - on biology. But the scientific consensus on the matter is actually different from what they imagine: Gender is a spectrum. If we want to preserve the binary, we can put male and female at the two poles. But there is far from empty space in between.
There are not just two options for chromosomes
XX chromosomes = female, XY chromosomes = male. We are taught in school that this is how gender is created. People with XX chromosomes usually develop a vagina, uterus and ovaries in the womb. XY creates a penis and testicles.
Sure, sex chromosomes are important, but gender is not created so easily. For example, there are people who look like women on the outside but have the “male” XY sex chromosomes in their cells, and vice versa. How is this possible?
A gene located on the short arm of the Y chromosome and called SRY determines whether or not testicles will form in the embryo. If, for example, this gene is not read due to a mutation, it remains "silent", i.e. testicles do not form despite the XY chromosomes. On the other hand, testicles can grow in people with XX chromosomes if the gene (probably during cell division) is transferred to the X chromosome and read.
This raises the question of how correct it is to determine sex after birth, as is currently done, solely on the basis of its visible external characteristics?
1.7% of people are intersex
Natural abnormalities in sex chromosomes are numerous. This can also have an impact on visible sexual characteristics, i.e. genitals. Among them, there are also several gradations between a fully developed penis and the externally visible part of the clitoris.
People who cannot be clearly assigned to one of the binary genders are called intersex or inter*. The United Nations (UN) estimates that 1.7% of the world's population belongs to this group. That's roughly the same as the number of redheads around the world. Since 2018, the gender of these people in Germany can be recorded in the birth register under the column "other". Different gender affiliation is also recognized in other countries, such as Australia, Bangladesh and India.
By the way: gender can also change later in life, or more precisely - the gonads. Chinese researchers have established this in a study on mice. The genes DMRT1 and FOXL2, which normally balance the development of the ovaries and testicles, are responsible. If there is a change in these genes, the gonads in adult mammals can change from one extreme to the other.
"Male" and "female" hormones are actually common
"Testosterone is the male hormone, and estrogens and progesterone are the female hormones." But that's not exactly true either. Men, women, and trans people have these sex hormones in their bodies. The levels of progesterone and estradiol (the most effective natural estrogen) in adults of both sexes are almost the same.
If you are looking for a binary in hormone levels, you should rather distinguish between the following two sexes: "pregnant" and "not pregnant" according to a review American study. Because only in pregnant women are the levels of estradiol and progesterone very unusual compared to other people.
Children cannot be distinguished by gender before puberty, if their sex hormones are looked at. It is only during puberty that testosterone levels begin to vary, so that on average men have more testosterone than women. But even this difference is overestimated according to recent findings - due to a gap in research, since testosterone was only checked in men, and estrogens - only in women.
Today, specific studies are being conducted on the hormonal overlap of the sexes. It has also been discovered that hormone levels depend to a significant extent on external factors and are not, as previously assumed, purely genetically predetermined. For example, future fathers have less testosterone during their partner's pregnancy. On the other hand, the supposedly female hormones estradiol and progesterone are increasingly formed when people compete for dominance - behavior that, as a stereotype, is assumed to be masculine.
Female and male brain?
"But women think very differently than men, something must be different in their brains!" Of course, there are differences between the brains of men and women. The male brain is on average larger. Individual brain sectors also differ in their average size, the density of connections, and the type and number of receptors.
However, even here, researchers cannot precisely identify the male or female brain. Each brain is quite unique and in its individual parts it rather resembles a gender mosaic. Incidentally, this also applies to the brains of transgender people, which have also been studied in detail: in terms of individual parts of the brain, trans people are sometimes closer to the gender they perceive themselves as, but sometimes closer to the gender they were assigned at birth.
For these reasons, the search for a categorical gender binary can be rejected. Any "biological" argument in this direction is simply not scientific. Gender is as complex and diverse as the people who wear it.
Author: Katya Shcherzyk