Adoption
I recently made a sim with the purpose to adopt. When it came time to adopt I got the option to choose from a bunch of different children from baby to child and it was pretty hard to just choose one. ...
Forum Discussion
I'm not saying that it's as good as what you're suggesting, but if you're adopting a toddler or a child, you could always go into cas and make them a sibling. A bit tricky with babies though, since we don't know what they'll actually look like.
