I don't think it's a bad idea at all. I don't think it would segregate either, the same as people without dogs or cats will read/post in cat or dog general. It wouldn't just be for pictures, it'd be a great place for all those 'new mother' questions or moms asking other moms questions about issues with their kids. I think it'd make it easier for people who might have advice to not miss these threads then, as threads in general are buried pretty quickly. Picture threads wouldn't be lost and buried so quickly under birthday announcements and games and general chatter.

I do think that new pregnancy and new birth announcements going in general would still be great even with a "PT kids" subforum.

Just some of my thoughts.