More Awesome Than You!

I have a custom neighborhood with 4 couples.   I used all Maxis genetics in this neighborhood. Most of their kids have correct genetics until I created a couple of pets.  In one of my couple the mother has black hair and the father has blonde hair.  Their last daughter has blonde hair.  I thought it was cool that she seemed to have inherited her fathers blonde hair bc black is so dominate over blonde and its never occured in my game to the second generation anyway.  I went and had a look at her genetics and she actually didnt inherit anything from her parents. She has all custom genetics.  I looked at the rest of the kids after I created these pets and they also have incorrect genetics.  I blame it on Pets and started all over again. So far everything is turning out as it should. I havent created any new pets since I discovered this either.

edit:  I created the pets by themselves so I dont get why they are affecting the whole neighborhood.

Ok, I don't have any kind of answer, just sympathies.