Yes, but I can see how its problematic for devs. You are doubling render count for certain scenes if you give players the option and you have to make sure the story stays coherent whether she's preg or not.
I have fond memories of some of the old Japanese VNs... stuff like Crescendo . Definitely not my style of game nowadays but that was the sort of game that was commonly available back in the day.
I won't completely discount a game strictly on ratings but I may take an extra minute or two to skim the reviews and game thread if something is really low, like in the 1.5 star area.