I wasn't quite sure where to put this, since it's not a problem with the mod, but a question about its coding. Does anyone know from a coding standpoint how twallan got the game to produce four babies in a Sim pregnancy? Like, was the script already hidden in the game files, or was it entirely new on his part? I'm wondering because I'd like to try my hand at a mod for more multiples (quints/etc.) if and when I learn how to mod the game beyond XML tuning. Thanks in advance, and sorry if my question is in the wrong place!

It wasn't part of the game, no. Woohooer replaces the give birth interaction with one that proxies the Sims entire pregnancy class with a custom one that handles quads.

It should probably be noted any other mod that does such would be incompatible with woohooer.

Good to know. Would it be possible for that custom pregnancy class that Woohooer provides to handle more than quads, so that maybe it could be used as a replacement for that part of Woohooer?