You should be able to do something like that in Sims 4 (which has literally thousands of modded sex animations). I never really understood how the timing of it was supposed to work in this game, since people don't age that quickly. In Sims, the average lifespan from birth to old age is like 50 days, so it makes sense that an MC could have a child who then becomes an adult within the span of a normal game session. In this game, that child would have to age a lot faster than the other characters. I don't know why that would be any more immersion-breaking for me than any of the other crazy stuff in this game, but the human mind is funny that way.