Been messing around with each of the bosses, and I think the only "Boss" that can get you pregnant at the moment is Wuelie, the Rabbit girl. I have tried REEEEAL hard to get the others to do anything, and nothing pops up. xD So it's a one time thing per play through of the demo, it would seem.
You can let Wuelie get you pregnant if you let her zap you with any of her attacks, and let her have her way with you. (You can't let her defeat you, and keep the pregnancy, either. Tried that. Didn't work. xD Oh well!) But once you defeat her, you can walk around with the baby bump. But seeing as this is a demo? Once you let Momo help you give birth? That's it for the singular piece of pregnancy, for now. Which is a shame. But a sign of awesome things to come! (Unless Mofu or Lip says otherwise.? /shrug)
Not complaining either. This little demo has been AWESOME so far. Can't wait for the game to get fleshed out and go all the way.
Here's to hoping that you can sex all of the Bosses, even after defeating them, and have pregnancy happen multiple times, as it's a nice little touch and it's drawn amazingly well. Only time will tell. ;3
Love the game Mofu, WOOO! Can't wait for release. Insta buy! <3