Both male and female hormones play role in making men masculine

Gender-specific behavior patterns are often chalked up to testosterone in men and estrogen in women. However, how these two hormones interact to control masculinization of the brain and behavior remained to be established.

A new study at the University of California, San Francisco, explains why the hormone issue isn’t so clear cut. The male hormone testosterone doesn’t work in ways that had been assumed when it comes to masculinizing the brain during development and making males behave a certain way when they’re adults, researchers found.

The study, published in the April 29 issue of the journal Neuron, found that estrogen, which is virtually undetectable in the circulation of most male species, can be derived from circulating testosterone in males. In the brain, this testosterone-derived estrogen can control many behaviors that are typically linked to males.