I tend to use custom skintones. Default and non default for skin and eyes. I had my Sim Gabriella marry Don and they had 4 kids. Three boys, who have green eyes (Gabriella has green eyes and pretty sure Don does as well), dark hair (from Don) and a lighter skintone that is closer to Gabriella's. The lightness/darkness of the skin tone doesn't bother me (my dad and mom have fairer and darker skin, and I am fairer like my dad, but not quite the same shade). The facial features though is where it would bug me if my sims had a kid that looked zero % like their parents.
EDIT: Their 4th child, a daughter is much closer to Gabriella, same hair, eyes, and the lighter skin tone.
