Same reasons, though, civilization and sex. You heard what I said. Look, any civilization violates the basic premise of the creation-evolution ethic, which is survival of the fittest. Survival is the keystone of life, and the weak or incompetent go under. So the offspring of the survivors are the fittest, those with the abilities and skills needed, and only the best of them survive and raise more offspring.
Civilization changes all that.
And partly because of Your teachings, Son, civilization protects all its people. Even the cripples, the incompetents and the defectives. It's simply the way evolution works, that's all. Anyway, it isn't survival of the fittest in a civilization. So the longer a civilization lasts, the lower the abilities of the average.