Right here:
Marhis's tuning modsThe mod is titled "Marhis-Genetics-Mutation1percent". I use it personally for Sims 3 so none of the children will grow up with their parents' hair and eyes. Try that one and see what happens. The facial genetics is something that couldn't be modded so they don't look like copy cats of their parents from what I understand by reading several threads about Sims 3 genetics from different forums.