First off, let me copy something from one of the gaming forums I frequent. (Forgive the spelling, but that is how it was posted.)
“The age of consent has steadily increased in industrial societies in so small part due to the social effects of the indistrial revolution. The need for more education combined with more labor saving devices resulted in people spending more and more time in school. It began as an artifical social construct called ‘childhood’, which justified mandatory government provided schooling. As educational requirement increased newer age classess were invinted so that this mandatory schooling could be extended. Now, with college education being almost necessary for survival a 22 year old is considered a child in some respects. ”
Now, I have heard it said that 26 is the new 18 for that exact reason. It used to be that most people stopped their education at 18; about the time most people graduate high school. Before high school was mandatory, 18 wasn’t nearly the magical number it is now.
Have you noticed that it is only that way here? In Europe, they let people we Americans would consider kids do far more, like drink, drive, and screw (though not at the same time). And in less industrialized nations, the rules are even laxer. It is only here in the epitome of First-world nations, the pinnacle of industrial might, that we are uptight about age.