I'm not entirely sure what they are called, but its something along the lines of "genetic skintones". I saw them on someones site a while ago, when the sims was not installed on my computer, and forgot to bookmark.
In the sims, I believe the sims get a skintone from either one of their parents, this skintone/mod made it so the child had a mixture of two. Say parent one was a #16 skintone and the other was #20, the child would be #18.
Could someone please direct me to a site with "genetic skintones"?