Scientists claim to have solved the mystery of the female orgasm - and it's all to do with ovulation. A study on mammal reproduction found orgasms help apes to ovulate but, because it plays no part in the reproductive cycle of humans, it is a redundant evolutionary afterthought.In many mammal species ovulation is started by the male, whose sexual stimulation of the female causes her to become fertile.But due to evolution, the clitoris has shifted from inside to outside the vaginal canal in humans, taking away the link between orgasms and reproduction.Said Yale Biology Institute researcher Gunter Wagner: "Prior studies have focused on evidence from human biology and the modification of a trait rather than its evolutionary origin."Since there is no apparent association between orgasm and the number of offspring or successful reproduction in humans, the sex scientists focused on the "feel good" hormones prolactin and oxytocin released post "climax". They found that, in many mammals, this reflex played a role in ovulation.The female ovarian cycle in humans, for instance, is not dependent upon sexual activity.Gunter, professor of ecology and evolutionary biology at Alison Richard, and Mihaela Pavliev, of the Centre for Prevention of Pre-term Birth at Cincinnati Children's Hospital, feel the trait that evolved into human female orgasm had an ancestral function - that was to induce ovulation.Pavliev added: "Homologous traits in different species are often difficult to identify as they can change substantially in the course of evolution."We think the hormonal surge characterises a trait that we know as female orgasm in humans. This enabled us to trace the evolution of the trait across species." ..