Testosterone and masculinity
Without testosterone, a foetus stands no chance of becoming male, of developing a penis and testicles, regardless of its genetic sex. It is the XY sex chromosomes of a male embryo that encourages the embryonic tissues to produce testosterone. This hormone starts a path of male physical differentiation. The truth is, babies start out as undifferentiated beings, sexually, and the default path of development from that neutral point is into the female form.
Unless the embryo produces testosterone, and its tissues respond correctly to it, at certain crucial stages in its development, it will become a female, regardless of its genetic sex. The neutral origin of our two sexes is seen in the histological analysis of adult male and female. For example, the clitoris and penis come from the same area of embryonic tissue and the g-spot in the vagina and the prostate gland also have their roots in the same place.
But even the production of testosterone by a developing embryo is no guarantee of maleness, such is nature’s capriciousness. There are varying degrees of adult intersex conditions which can be traced back to some failure of embryonic development.
Sometimes, for example, the chromosomally male baby, distinguished from his female sisters by his XY chromosomes, has a genetic mutation which makes his tissues more or less unresponsive to his own testosterone or, more accurately, one of its derivatives called dihydrotestosterone.
The results of this unhappy accident of nature are categorized by the medical profession on a scale of severity from 1 to 7: 1 being normal male, 2 being a bit feminized (probably a fertile male with perhaps a small but possibly abnormal penis), all the way through to 7, which is a syndrome known as testicular feminization.
This is when the XY individual, though normal by any other standard of humanity – intelligence, personality, physical dexterity, body form – has XY chromosomes but appears to be, from birth onwards, a female, and often later develops into a very feminine woman at puberty, with rounded breasts and an attractive feminine body, but with no internal female sexual organs. But, assuming everything goes OK, a baby with XY chromosomes will develop testicles and a penis, and all the internal male bits to go with them.
Later, at puberty, his testicles become active and produce testosterone, and he develops the characteristics of an adult male. It might follow that the higher the level of testosterone in a man’s body, the more sexually driven he feels, and the more intense his sexual motivation. However, we need to carry the logic a bit further. High testosterone men are also more driven and competitive, and legend has it, more aggressive, though the relationship between cause and effect here is somewhat dubious.
If you give men more testosterone, they display more of the personality characteristics they already have – for example, an unaggressive man, given testosterone, does not become aggressive. This might mean that high levels of testosterone are the result of competitive success and high levels of aggression, not the other way round. There is some evidence to support this idea. For example, in shadow work, practitioners tend to find that sexual drive, masculinity and aggression are not directly related. Aggression seems often to be a characteristic generated by a man having been surrounded by violence and aggression in childhood, or by taking excessive steroids for body building in adulthood. (In therapy directed at the control of excessive rage or anger, a shadow work practitioner would work with the part of the personality known as the Warrior archetype to encourage the integration of repressed aggressive impulses into the whole of a client’s conscious personality.)
As a man gets older, his effective level of testosterone falls, partly because his testes become less efficient, partly because his physiology becomes less effective at removing oestrogen from his system. (Oestrogen is produced in all men, and blocks the molecular receptors on his cells where testosterone usually rests. One of the liver’s jobs is to remove the estrogen.)
This is one reason why men get less sexual as they get older. Testosterone replacement therapy can deal with the problems that come with declining testosterone: depression, reduced sex drive, impotence, lower motivation. Unfortunately many doctors don’t accept that testosterone replacement therapy for older men will cure impotence. They say many older men are impotent but have normal levels of testosterone.
This is false logic because first you need to know how a man’s testosterone levels have changed over time – not all men are equal to start with, as you can see by the wide range of testosterone levels that are regarded as “normal”. Second, you can’t just measure total testosterone – you have to asses how much is available to the man’s body tissues. Often this may be radically different to the amount in the bloodstream.