For example, the old 11-plus examinations, which sorted students into secondary schools, were skewed deliberately: boys, considered less mature than the opposite sex, were not required to perform to the higher standard set for girls.
As parents, we need to determine which games we feel comfortable with our kids playing and which games are too mature or too violent or have explicit sex scenes two-thirds of the way through.
Dr Leonard Sax, the founder of the National Association for the Advancement of Single Sex Public Education, even claims a neurological reason for his cause: girls and boys mature at different rates, so they need different teaching methods.