I'm inventing a race for a roleplaying campaign, and I thought about making them live really long lives (or even be immune to ageing) and not be fertile, but I still want them to be male and female in appearance even though they don't have a reproductive system.
Is there a way to give a somewhat scientific (it doesn't have to be 100% solid, just believable) reason why they can appear as male and female without having genitals? Can they have gender-determined hormones for some reason?
to clarify, I decided that the members of this race were created one by one by a god, who decided to make them not reproduce but instead live indefinitely long lives (virtually infinite). I was asking for a way to explain the existence of gender traits even without having a reproductive system, just to avoid having to say "yeah it's because that god wanted them that way and that's about it". I mean, is there any reason for there to be gender traits (such as breasts or more developed muscular structure) other than reproduction?