As a massive pregfag, I wish there was a way to make money off impregnating slaves in FC
You can filter the embryos for perfect genes and grow them into slaves that sell pretty well, but the value you get from that is pretty small relative to other factors and you have to be pretty late in the game to have access to it
Any other good games where you impregnate (or get impregnated but I prefer the other way around) to help you achieve gameplay goals rather than as a byproduct or afterthought?