"For most of history, men's and women's different roles in life were assumed to be mainly innate and unalterable. This was challenged in the west with the rise of feminism in the second half of the last century. Perhaps the different behaviours of boys and girls arose because of cultural norms: parents praising boys for romping and smashing toy cars, for instance, while expecting girls to be more reserved and play with their dolls.
Around the same time, though, new light was being shed on the biology of gender. In the womb, we all start out more or less female, until sometime between six and 12 weeks of pregnancy. Then, in male fetuses, a gene on the Y chromosome causes certain cells to make testosterone, which leads to the development of the penis and testicles. Female fetuses do not have this "testosterone bath" and so develop female reproductive organs.
But the sex hormones' influence is not limited to our gonads: they also play a key role in the brain's development, influencing the architecture of various neural circuits. As well as establishing these anatomical differences, the sex hormones presumably affect our behaviour as adults too, as their receptors have been found in many brain regions.
Understanding the ways in which male and female brains differ has become a hot topic in neuroscience, particularly in the past decade with the growth of brain scanning as a research tool." By Kayt Sukel via New Scientist / continue reading