This isn't really helpful for those playing with no CC and only a minimal set of mods, but just wanted to point out that males can be impregnated without alien involvement. A male who becomes pregnant the old fashioned way (?)...no wait, there has to be a better way to say that. Males who are actually carrying their own babies, having been impregnated by another sim who was not doing alien probe things to make them a mere surrogate, actually do require maternity (paternity) clothes or else their mid-section disappears when the pregnancy progresses to where the baby bump is supposed to show. They do not just become fat, they actually look pregnant. :)