It is known as the happiness chemical, but could serotonin also influence sexual preference? It certainly seems to in mice.

Serotonin is normally associated with mood – particularly feelings of well-being. But when Yi Rao of Peking University in Beijing, China, and his colleagues genetically engineered female mice so that they could no longer make or respond to serotonin, it appeared to affect their sexuality.

Although they would still mate with males if no other females were present, given the choice, the rodents preferred sniffing and mounting females.

This is the first time that sexual preference has been reversed in female mammals without the use of sex hormones. Serotonin can modulate olfaction, but the team ruled this out. Instead, it seems the chemical has a more central role in controlling sexual preference.


“It’s possible that the well-known effect of early sex hormone levels on partner preference and the serotonin mechanism described here are completely independent mechanisms,” says Simon LeVay at Stanford University. “However, it’s also possible that the early sex hormone mechanism works by an effect on the serotonin system. In other words, serotonin systems may be part of the cascade of signals that translate sex hormone levels during development into sexual partner preference in adulthood.”

Journal reference: PNAS, DOI: 10.1073/pnas.1220712110

This article appeared in print under the headline “Chemical roots of sexual attraction”