I sometimes have abnormal vaginal bleeding.

And when people have done a variety of studies, they have learned things such as, when a baby is born, during vaginal delivery you get colonized by the microbes from your mother.

Of course, there are the bases, which refer to specific sexual activities that happen in a very specific order, ultimately resulting in scoring a run or hitting a home run, which is usually having vaginal intercourse to the point of orgasm, at least for the guy.