I peeked to see what Castor and Heather's son will look like when he grows up, and he is gorgeous.
I always use Castor for having kids. Even though he's usually a romance sim in my games, I still have him pair up with my most played sim, Freak, they always have pretty kids. lol They always look like Freak but I keep trying to see if any of them have Castor's features, so far, in several games no matter who I pair Freak up with, all his kids look like him, must be his custom skin and eyes.
This is the last 3 of their kids in the current game I'm playing:
Castor and his daughters--the teen pic then their Uni pic--(click on the pic for the larger view) and the last 3 are their son, again looking like Freak.
And this is Freak with their son
As long as I've been playing Castor, I can say I haven't had any ugly kids from him. He's the only Maxis sim that I allow have children, any others are all my own CAS creations, there's enough ugly sims in the game, I don't need to be adding more to them.