Well this isn't new or weird but I thought I'd share with you guys anyway:
I decided to use the Surrounded by Family LTW as a bit of an experiment in Sim-genetics.
One parent is a CAS Sim with BRIGHT RED hair and crystal blue eyes, the other is Agnes Crumplebottom [Original, yeah I know].
We have the 5 kids.
1 has her father's hair and mother's eyes.
1 has her mother's hair and mother's eyes.
The other three leave me scratching my head.
Where did the black/brown hair and hazel eyes come from? I did no editing in CAS [About the only changes I did were to hairstyle, but not color. That was accomplished outside of cheats].
Edit: After looking at the family tree, I can very well see that the hair and eyes might have come from Agnes' parents, as Cornelia has dark hair.