Well, if you're arguing about the length of childhood (which IMHO shouldn't be the basis for age of consent, decision-making maturity should be), then we have not lengthened human childhood.
Socially, we've delayed the age when youngsters achieve self-sufficiency, start working, etc; but instead of prolonging "youth" currently our habits (most likely due to food industry) have achieved earlier age of puberty than before; biologically those kids are maturing sooner for having kids of their own.
Socially, we've delayed the age when youngsters achieve self-sufficiency, start working, etc; but instead of prolonging "youth" currently our habits (most likely due to food industry) have achieved earlier age of puberty than before; biologically those kids are maturing sooner for having kids of their own.