[Marilyn]

I've studied genetics, of course, it was 30 years ago, so they know a lot more now than they did then, but it's actually very easy to understand why traits skip a generation or why one sibling with have it and another will not. We did experiments breeding, of all things, fruit flies and the formulas they taught us for predicting the probability of a trait exhibiting itself were very accurate even then.

If a trait is carried on an uncommon recessive gene, it will not exhibit itself until it is matched by another recessive gene, which could take generations to occur. That was one of my more memorable courses in college. Only reason I took it was because I was majoring in Biology/Pre-Med at the time. Those were the days!! Don't I sound old!!