My kids tend to be a mixture. My favorite sim is green and I love to make my sims of every color that she interacts with just to mix it up.
Their kids come out rainbows (not literally.) I get a bunch of different combinations. Her current husband is bright red. Some of the kids have the red hair and the green skin, some are light pink, some are bright red with aqua hair. One of my favorites things is to see what color the baby is and then what sort of hair they get when they're a toddler or child. I get a fair bunch of bald toddlers, which is a tease.
I suggest you have more kids.