1972 High school Biology class taught that a Roan is the 3rd birth of the same two parents which is always different than the other 3 in 4 births! I have found this to be true, in my personal observations! From different species of animals including humans! The 3rd birthed by same 2 bred animals, is anomaly! Thus it will be an oddity. The Roan equine developed from this oddity. Per HS Biology class. Does anyone else remember this?