complementary differences

The birth of differences

It is not until six or seven weeks after conception that the unborn baby “makes up its mind”, and the brain begins to take on a male or a female pattern. We know that the genes, carrying the coded blueprint of our unique characteristics, make us either male or female. In every microscopic cell of our bodies, men and women are different from each other; because every fibre of our being has a different set of chromosomes within it, depending on whether we are male or female.

But the genes alone do not guarantee the sex the sex of a child. That depends on the intervention, or the absence, of the other factor in sex determination – the hormones. Whatever the genetic make-up of the embryo, the foetus will only develop as a male if male hormones are present, and it will only develop as a female if male hormones are absent.

Embryonic boy babies are exposed to a colossal dose of male hormone at the critical time when their brains are beginning to take shape. The male hormone levels then are four times the level experienced  throughout infancy and boyhood. A vast surge of male hormones occurs at each end of male development: at adolescence, when his sexuality comes on stream, and six weeks after conception, at the moment his brain is beginning to take shape.

But as with the development of the rest of the body, things can go wrong. A male foetus may have enough male hormones to trigger the development of male sex organs, but these may not be able to produce the additional male hormones to push the brain into the male patterns. His brain will “stay” female, so he will be born with a female brain in a male body. In the same way, a female baby may be exposed in the womb to an accidental dose of male hormone and end up with a male brain in a female body.

Now it is accepted, to a greater or lesser degree, by virtually every brain specialist or neuroscientist. If the hormones hold so much of the answer to our behaviour, mental attitudes and outlook, could they also dictate our sexual inclinations? The answer is yes. Sufficient, for the moment, to mention just as some drugs taken during pregnancy can misdirect the development of the foetal brain , so a chemical imbalance in the womb can also alter sexual inclinations in the eventual adult. We know how to make homosexual rats and monkeys. Some scientists argue that we know how to prevent homosexuality in men – before birth.

How the brain circuitry is arranged affects more than our sexual inclination. It will make us, male or female, tend towards different attitudes, responses, feelings about ourselves and others, priorities… all the hundreds of differences noted throughout the ages by poets, writers and ordinary men and women, in blissful scientific ignorance. It even explains how and why we think differently.