Firstly, impregnating Collins doesn't have to be bad. DarkDank's point about controlling Collins is fair. Additionally, if the MC is in the kid's life enough, maybe he could eventually teach the child also to dominate Collins as well (not necessarily sexually). That wouldn't be so bad. ("I said, 'Mom', that I'm not going to do that!")
Secondly, I hate to break "bad" news to you, but there is already at least one pregnancy variable being tracked in the game, and it was potentially (depending on choices) incremented with this latest update. So from all signs, pregnancy will be a thing in the game if you make the choices leading to it.