I will probably design specific icons to represent biological functions: sperm on one side and egg on the other. I'd like to avoid any gender based symbolism since most of them are hetero coded UwU Plus it's kinda cool sometimes to come up with fun new icons XD but thanks for your ideas it's a very interesting topic indeed!!
I'm very aware of the gender icons, but I actually need the opposite, I need something to describe the reproductive organs! So the player can easily spot who can be pregnant and who can inseminate. But I'm roughly going with icons like: egg vs sperm cell. Works for all creatures UwU
As for the genders, they're not really used for the moment in the game since I don't planned to add dynamic dialogues, but who knows!!