Studies seem to say that semen is an anti-depressant. This means that it causes women not to feel depressed or sad. The studies found that when men had sex with women without using condoms, and the men's semen was taken into the women's vaginas, the women had better moods and felt happier. Scientists do not yet know if the same thing happens when semen is swallowed after oral sex, but some of them think it may.