>>716509610 (OP)Its kind of a hard thing to build mechanics around.
Only game I can think of that really tried was Strive for power
I liked how it worked, you could impregnate your npc companions, they would get stat debuffs for the duration and needed extra care. but you could in theory breed superior soldiers.
It was a clunky system. it took a long time which clashed with the 'story' of the game, I think a game that did it properly would need to use something like month long turns so you have the right balance of control and pacing.
I know there are a few weirdo fetish games that just have pregnancy without any offspring, but I think that kinda defeats the point.