Imagine what would it would be if there was people of a gender different from male and female and having different genitals.
Most Helpful Girl
Most Helpful Guy
There was an Isaac Asimov Story where there were an alien race with three sexes all of them necessary for reproduction,
Asimov was famous for not using sex scenes but his publisher wanted one so he wrote one so deliberately titillating that his publisher never bothered him again about it