Regression in genetics is different than regression to the mean in statistics. The genetic regression depends on the trait under study. A tall family will have tall kids. They will not suddenly become Hobbits. And regression in genetics is still a way to "account" for things that cannot be measured and hence are "random" in appearance.
All I know is that low IQ runs in families, which is how you can represent multiple generations for the same disability of mental retardation (70 or below, for my purposes).
