Charles Darwin

About 10 percent of humans worldwide are the product of some inbreeding, and the potential dangers were little understood as recently as 150 years ago, when Charles Darwin did some of the earliest research on inbreeding, in plants.

Since he was married to his first cousin, historians say, some of his interest was driven by concerns about his own children's health

Source: http://www.philly.com/philly/entertainment/20110425_In_royal_commoner_marriage__a_happy_mix_of_genetic_diversity.html