Dr Orbach said: "In dolphins, the clitoris is positioned at the entrance of the vaginal opening and in direct contact with the penis during copulation, unlike the external position of the clitoris in humans.

In this study, the reproductive mode, male's mating capacity, influence of female's age and density on male's mating capacity, as well as the influence of copulation on female's longevity were investigated under the laboratory condition.

Copulation in most species is followed by internal fertilization, with the transfer of sperm to the female assisted by "nurse cells" (Fretter & Graham 1962, Borkowski 1971).

In this study we used an experimental neuropathy model to investigate whether NP affects reproductive parameters in mice by examining the number and maturity of oocytes and the copulation ratio.

Cricket reproductive behavior includes female attraction by means of the calling song and sexual recognition by antennation (Hardy and Shaw 1983, Balakrishnan and Pollack 1997), which triggers courtship and copulation (Alexander 1966, Alexander and Otte 1967, Alexander 1975, Otte and Cade 1976, Otte 1992, Kortet and Hedrick 2005).

copulation, he received an invitation from an anonymous dignitary.

Although you did not state if you are married or in a relationship, some cases of Oligospermia can still go on to have children if copulation with their spouses take place during their partner's fertile period.

Although warning against champagne and copulation, Dr de Caestecker says:"We want women to enjoy the festive period and hope those trying to conceive get the Christmas present they are hoping for.

Reproduction increases an individual's fitness directly; however, the act of copulation can incur fitness costs.