What's the purpose of male nipples? This question has probably been asked by every man and woman who has ever lived. Are they vestigial? Did men nurse babies at some point? The very existence of male nipples raises a ton of mystifying questions. But in reality, science is well aware of the numerous reasons for why male nipples exist, and the answers are refreshingly straightforward.
For one thing, humans have a lot of body parts that just don't seem to make a lot of sense. The appendix, pinkie toes, wisdom teeth - they all seem somewhat random. Male nipples aren't all that different, though they are probably the most noticeable bodily outliers. And yes, they are there for more reasons than to just to add some visual interest to the male chest.
Why men have nipples is a fascinating conundrum. The short answer to the question of "why do guys have nipples?" is that all fetuses begin as female, and develop certain female characteristics. The long answer involves testosterone, natural selection, and body chemistry.