Frimlin

Try adding the babies in the normal way when you edit the household from the edit world window. It may be using the shift-click cheat just isn't as stable.

Ahh, okay, so that was why you were using the cheat anyhow. Can you try removing 2 family members via edit household, add in the babies, then use the shift-click cheat to add the 2 people you removed? May work better adding sims rather than "baby objects."

I don't know off-hand without loading up the game. But I have a feeling there isn't a special option, no. But I might be wrong!