Good idea about checking August birthdays against September birthdays. That would be easy enough to go back and check for someone who had the time and inclination to do so. I don't think it would be too hard, but it would be time intensive.

Don't think you'd find what he's suggesting. Given that these age gaps in grade cohorts have always existed, even well before men stopped enrolling in college. Common sense tells us "girls mature faster" is not a valid reason.

In fact, all the reasons put forth by men (MRA types) don't track. Common sense and historical context easily excludes these ideas.

I'd like to see if it's more due to economic reasons or if it's because parity was reached, like we've seen in some professions and that's led to devaluation of education in the male mind because now it's considered "feminine".

Those two things seem the most likely to me and my personal belief is that there's some confluence between the two.

Good article.