Just wanted to comment that it has all to do with genes and dominant and resesive genes. Think of Mendle's flowers Red flower and white flower makes a pink flower.
Actually, Mendel didn't encounter those results, though it doesn't mean his genetic principles were incorrect for the data he collected. The result he obtained was that a purple flower + white flower = purple flower hybrid (the purple flower phenotype clearly was dominant). And when he crossed the hybrids, purple flower + purple flower = 75% purple / 25% white.
The example you gave of red + white = pink is actually a result of incomplete dominance.
Recessive vs. dominant genes do, however, explain how blue-eyed Quentin and Angelique could have legitimately produced brown-eyed David.