Impregnation fantasies are a thing. Women wanting to become pregnant or ‘bred’. Men wanting to do the ‘breeding’. Even men wanting to become pregnant have them it seems as lines between gender become more blurred. There’s quite a few people talking about them on reddit and other such forums and there’s a wealth of porn on the matter. If we’re including pregnancy in general it’s almost always listed as a separate category by itself on most sites so it seems it must be pretty popular.