NatureScienceSexual difference

Sex differences in brain

We often talk about “sex differences in brain”. In fact, there are a variety levels of sex differences including a slight difference that we can detect only after the careful examination of 100 males and 100 females, and an obvious and robust difference that anyone can see. The hypothalamus shows clear sex differences, which are determined by the hormonal environment during development. In other words, the developing brain has sensitivity to hormone, especially testosterone. We found that a transcription factor, PTF1a, is essential for acquiring the sensitivity to hormone milieu during development.