On the contrary, I think that genes for gifts, talents, and abilities, broadly speaking, do pass down to subsequent generations. It is true that not all children of doctors, lawyers, and teachers follow in their parents’ footsteps, but there is indeed more of a tendency. You definitely see it among the professional classes and the affluent, upwardly mobile in this country. And it is not wholly genetic. If there is a strong expectation that you will pursue excellence in general, you are more likely to do it. I have known of families where it was just expected — “you will make something out of yourself”, being “just average” isn’t treated as an option. (Many times these families tend to be rather uptight and even neurotic, but that’s another story entirely.) And high-achieving, more intelligent, more educated people tend to marry one another, thereby perpetuating and reinforcing good genetics as well as ambitious habits.
I may not have painted my scenario clearly enough, and I was making some broad presuppositions, one of those being that, throughout much of Catholic history, advanced education was pretty much solely the province of the Church and served her ends, prime among these being the clergy. Priests were better educated than anyone else. Assuming that the most intelligent young men would be encouraged to pursue priestly vocations, or would pursue them of their own volition (reasoning that, among other things, they would be able to get the education that goes with such a vocation), then this takes them out of the gene pool. To a lesser extent, this would also hold true for religious, both male and female. Simply put, many of the smartest ones didn’t reproduce. Now let this trend trickle down through 40 to 50 generations. When children are born, many (if not most) of the very intelligent ones are skimmed off into celibate vocations — “the cream rising to the top”, you could say. I think this could depress the IQ of the population taken as a whole.
