BY Michelle Garcia
August 11 2011 1:45 AM ET
Brain response to hormones differs between lesbians and straight women
2007: Swedish researchers found that lesbians' and heterosexual men's brains reacted similarly when stimulated with certain hormone. In contrast, the brains of lesbians and heterosexual women react differently to sex hormones, adding to the argument that homosexuality is an innate trait rather than learned behavior.