BLOOMINGTON, Ind. -- A new study of American singles found that during sex with a familiar partner, men have the highest orgasm rates. On average, men experience orgasm 85.1 percent of the time, with their sexual orientation making little difference. For women, however, orgasm occurrence is less predictable. On average, women experience orgasm 62.9 percent of the time during sex with a familiar partner -- and this pattern varies with women's sexual orientation, with lesbian women experiencing orgasm more often than heterosexual or bisexual women.