Where this line of argument goes wrong is that the issue isn’t whether the adolescent years is the best age for a girl to become a MOTHER but rather whether it’s the best age for her to become a WIFE. If a man acquired a 12 or 14yo wife she wouldn’t typically start reproducing at that age but rather several years later at about 17. That’s the whole point. In order to monopolise a girl’s reproductive lifespan and get as many offspring from her as possible a man needed to acquire her some time before she started reproducing. There would be rare cases where a man’s wife got pregnant at 12 or 14 and died in childbirth or something but this isn’t what would TYPICALLY happen. The few cases of early pregnancy wouldn’t have made it maladaptive for men to form sexual relationships with adolescent girls anymore than the rare cases of people choking to death eating steaks would have made it maladaptive to eat meat.

What we want to know is the reproductive success of the males as a function of the age of the females they pursue and acquire: are men who acquire 14yo wives more or less reproductively successful than men who acquire 20yo wives etc? What those statistics show is the reproductive success of the females as a function of the age at which they start reproducing. They’ve got the wrong statistics and it’s really fucking laughable. The statistics only show that it would be maladaptive for girls to start reproducing in their pubescent years. They tell us nothing about the reproductive success of men who acquired pubescent girls as wives.

In prehistoric societies the typical 20yo would have already had a baby or two and started using up her fertile years. The typical 14yo would still be nulliparous and have all her fertile years ahead of her. Men who acquired 14yo wives would have got more offspring from them than men who acquired 20yo wives. It’s not complicated.