WATCHING MULTIPLE MEN HAVE SEX WITH THE SAME WOMAN STRENGTHENS SPERM.
Consider this: In a study in which researchers collected straight men’s ejaculate after they masturbated to one of two different pornos, they found that guys who viewed a gangbang scenario in which multiple men were having sex with the same woman released more active sperm than guys who watched a video of lesbian group sex. In other words, it seems that men are unknowingly increasing the sperm level in their ejaculate in response to the specter of competition.