In Alison's Alley, we talked about it quite a bit, and determined that were a lot fewer fertile men around, so babies were a big deal, and fertile men were in demand. We didn't really delve into that area of the game too much, what with the rest of the crazy, but it's worth thinking about.
In the Luxor, it's not as big a deal, apparently, although a healthy baby is possibly note-worthy.
Reasonable stances:
People are less fertile because of (pick one) the maelstrom, the crap in the water, wicked poor nutrition and medical care, lack of sexual partners, other.
People are the same as now, but fewer babies are born alive, because (pick from above).
People are more fertile, because of the whole lack of contraception thing, plus maybe the 'replenish the earth' thing, and also the sex.
I think whatever you pick for each game is good. And I'm liking this thread for my own nefarious MC purposes.