"Men are very rigid and specific about who they become aroused by, who they want to have sex with, who they fall in love with," says J. Michael Bailey, a Northwestern University sex researcher and co-author with Chivers on the study.
By contrast, women may be more open to same-sex relationships thanks to their less-directed sex drives, Bailey says. "Women probably have the capacity to become sexually interested in and fall in love with their own sex more than men do," Bailey says. "They won't necessarily do it, but they have the capacity."
Bailey's contention is backed up by studies showing that homosexuality is a more fluid state among women than men. In another broad review of studies, Baumeister found many more lesbians reported recent sex with men, when compared to gay men's reports of sex with women. Women were also more likely than men to call themselves bisexual, and to report their sexual orientation as a matter of choice.