Schooled for failure
But in advanced countries, children spend the majority of their waking time at school -- that is, in an environment where they are surrounded mostly by other children. Teachers may be authority figures (though arguably this authority has deteriorated over time), but most of the available role models in the immediate environment are other children. Thus children see much less adult behavior than they normally would, and have less opportunity to assimilate it -- instead, they see and absorb each others' behavior. One would expect this situation to lead to a steady increase in immature behavior among adults, generation by generation, starting soon after the imposition of universal schooling. Some would say that this is indeed actually happening.
Education is a necessity in the modern world, and it may be that this impaired socialization of the young is an unavoidable price we pay for it. However, even if we cannot improve the situation, there is an obvious way of making it dramatically -- and unnecessarily -- worse. I'm referring to gender-segregated schooling.
Unless they opt for careers as monks and nuns, the adults whom today's children will become will not live in single-gender environments. Confining them to such environments will limit their socialization even further by eliminating most opportunities to interact with the opposite gender, which will thus become that much more mysterious and unknown to them. Schooled in this way, then plunged into the adult world, their ability to deal with people of the opposite gender and form normal relationships with them will be that much less developed.
If this idea catches on, expect an upsurge in failed relationships when the generation subjected to it grows up -- with sad consequences for the succeeding generation of children which these unfortunates will produce.