I use to believe that a healthy male could get a young woman pregnant just by kissing her. The sperm would be in the guy's saliva glands and transfer to the woman via saliva. Of course that was before I found out about vaginas and I thought that babies would pop out of the woman's stomach and tear through her flesh. Sort of like puncturing the foil seal on a bottle of antifreeze with ball point pen.
Not like Alien?