ColinsMum, I fully expect Danish parents to have children that regress toward Danish means, not human means, not primate means, nor mammalian means. This effect was observed and quantified in the 19th century.
From Wiki:
"Galton coined the term regression to describe an observable fact in the inheritance of multi-factorial quantitative genetic traits: namely that the offspring of parents who lie at the tails of the distribution will tend to lie closer to the centre, the mean, of the distribution."
What I don't know is how knowledge of the grandparents or even great grandparents would affect the expected outcome. It seems to me that if we know the parents and grandparents were all tall, then the regression effect would be reduced (compared to cases in which we know nothing about the grandparents), but I don't think it would go away.
