Well. Now you've all done it. Joke around like this and Larian will do it because they think it's fun.
Now you're going to get dice rolls for sex scenes and who knows? Maybe they'll throw in a Pregnancy mechanic to boot - I mean, provided it's a heterosexual encounter. Roll a 1 on a 20 sider and uh oh! Now you're a pregnant woman with a tadpole, or your companion is. Situation SO much worse.
Ah, but then we'd suddenly have to have abortion mechanics and options, and also birth control and so forth. But hey! We want realism, right?
Of course, I'm kinda kidding, but also making a small point. Some arguments are that they want more realistic sex in the game because they want more realism. Well. Just how far do you want that to go?
Imagine how much more intense your situation would be if you or one of your companions became pregnant while having a tadpole in your heads.