The male is a biological accident: the y(male) gene is an incomplete x(female) gene, that is, has an incomplete set of chromosomes. In other words, the male is an incomplete female, a walking abortion.... To be male is to be deficient, emotionally limited; maleness is a deficiency disease and males are emotional cripples.

Woman's reproductive organs are far older than man's and far more highly evolved. Even in the lowest mammals, as well as in woman, the ovaries, uterus, vagina, etc., are similar, indicating that the female reproductive system was one of the first things perfected by nature. On the other hand, the male reproductive organs, the testicles and the penis, vary as much among species and through the course of evolution as does the shape of the foot — from hoof to paw. Apparently, then, the male penis evolved to suit the vagina, not the vagina to suit the penis.

To say that genetic differences are relevant to hetero- and homosexuality is not, however, to say that there are “genes for homosexuality” or even that there is a “genetic tendency to homosexuality.” This critical point can be illustrated by an example I owe to the philosopher of science, Elliott Sober. If we look at the chromosomes of people who knit and those who do not, we will find that with few exceptions, knitters have two X chromosomes, while people with one X and one Y chromosome almost never knit. Yet it would be absurd to say that we had discovered genes for knitting. The possession of two X chromosomes causes an embryo, with rare exceptions, to develop into an anatomical and physiological female, while the possession of a Y chromosome leads almost always to male development, and in our culture women are taught to knit while men are not. The beauty of this example is its historical (and geographical) contingency. Had we made the observations before the end of the eighteenth century (or even now in a few Irish, Scottish and Newfoundland communities), the result would have been reversed. Hand knitting was men’s work before the introduction of knitting machines around 1790, and was turned into a female domestic occupation only when mechanization made it economically marginal.

Our sex is ultimately laid down by our genes.

A predominantly masculine type to the external genitals, and even the presence of s, is compatible with a feminine habitus of body or with entirely feminine feelings and instincts, or with both. Thus was brought up as a girl until the age of 22, when she was pronounced a male by a court of law because possessed of a complete male genital apparatus—, though small and ; with a testicle in the right lobe, the left testicle resting in the and apparently in fatty degeneration; distended by sperm, which, however, contained no spermatozoids; rudimentary . The misinterpretation of sex had been due to presence of a central cleft in the scrotum, simulating a and terminating in a cul-de-sac six and a half centimetres deep. The rectification of this mistake filled the subject with such despair that he committed suicide.

Men, embryonically speaking, are imperfect women, as you know.

Every fetus becomes female unless it is steeped in male hormone, produced by a signal from the testes. Before birth, therefore, a male is already beyond the female. But to be beyond is to be exiled from the center of life. Men know they are sexual exiles. They wander the earth seeking satisfaction, craving and despising, never content. There is nothing in that anguished motion for women to envy.

Just as it sometimes happens that deformed offspring are produced by deformed parents, and sometimes not, so the offspring produced by a female are sometimes female, sometimes not, but male, because the female is as it were a deformed male.

All of this is men’s genetic heritage. However, men’s genetic heritage is in conflict with their genetic future.

Males are people with the type of body which, if all things are working, are able to produce sperm. Women are adult human females. Men are adult human males. There are only two sexes in humans.
No change of clothes or hairstyle, no plastic surgery, no accident or illness, no course of hormones, no force of will or social conditioning, no declaration can turn a female person into a male.

...femininity in boys and homosexuality in men are probably caused by incomplete masculinization of the brain during sexual differentiation.

In order to approximate those shapes and attitudes which are considered normal and desirable, both sexes deform themselves, justifying the process by referring to the primary, genetic difference between the sexes. But of forty-eight chromosomes only one is different: on this difference we base a complete separation of male and female, pretending as it were that all forty-eight were different.

It has a special biological character. Let us take one simple, down-to-earth criterion for that: we are the only species in which the female has orgasms. That is remarkable, but it is so. It is a mark of the fact that in general there is much less difference between men and women (in the biological sense and in sexual behaviour) than there is in other species. That may seem a strange thing to say. But to the gorilla and the chimpanzee, where there are enormous differences between male and female, it would be obvious. In the language of biology, sexual dimorphism is small in the human species.

The fact is that we don't know enough about hormonal effects on the human brain to have a very specific theory of how Danny's brain could have developed in a feminine direction while his body developed masculine. If Danny's body also showed signs of feminine development, this would support nature theory, but the lack of anatomical femininity does not disprove it. There has been essentially no research on boys like Danny that is directly biological. Short of dissecting the brain of a feminine boy and comparing it with normal boys' and girls' brains, it is unclear what we would even look for. However, the best conceivable direct test of nurture theory has been tried, and it failed. Amanda became Jason again.