“… According to a new study from economists at the University of California at Davis, starting school in the afternoon gave a surprising boost to boys. In the months when their classes were held in the afternoon, boys got slightly better grades on their assignments and tests. It wasn’t enough to totally erase the gender gap, it did close 12 to 16 percent of the difference in grades between boys and girls.” …
https://www.washingtonpost.com/news/wonk/wp/2016/08/05/how-sleep-holds-back-boys/