I always look at some of the kids; I can't help myself. I pick the heirs before they're born, for storylines, and assign the traits for the career/hobbies/skills I want to play forward, so appearance doesn't have any bearing on my decision. In big families, I might not care much about the looks of the spares, so maybe I don't bother peeking unless I'm curious.
Having said that, sometimes an intervention becomes necessary. Lucky for me, NRaas enables rerolls and "play with genetics" sessions, or else I might be stuck with this YA:
https://i.imgur.com/zEeRz55.jpg
For the record, he doesn't have bad genetics overall, just some unfortunate proportions. For reference, here he is gender-switched:
https://i.imgur.com/y1x8Jq1.jpg
But the lesson here is it's important to find out early. That way, you can do whatever you deem necessary.
