Mainly because it's a huge turn-off for me, personally. I don't mind adding things I'm neutral towards, but anything I actually dislike I won't add. If you enjoy pregnancy content, that's fine, but it's just not for me.
Yes, exactly the same reason for those two. While it might work with the story, I'm just not into it, and thus it would probably turn out subpar - I'm lacking the subjective understanding of what actually makes these things desirable, and I don't think reading up on something like that can substitute actual, felt desire/attraction.
You're right, of course. I assume that's a big part of it for a lot of people - or even the whole reason.
It doesn't change anything, though, because it clashes with my personal views regarding pregnancy
What I will say is that there is a chance for pregnancy in the story's epilogue. At least one of the girls (no details; don't wanna spoiler) lends herself well to the role of a mother, so I may make an exception for her/them. But as I said, it's not guaranteed.