Young people are forever shocking their elders, and elders, however shocking they themselves may have been to their own elders once upon a time, never fail to play their generation's perennial role of shocked onlookers to shocking youthful behavior of one sort or another.
Not very long ago, well within living memory, parents found their children's sexual behavior shocking. Sex was so open, so free, so ubiquitous, so uninhibitedly taken for granted. No hiding, no guilt, no confining it against nature within institutional straitjackets like marriage. This was the sexual revolution, brought about by the youth explosion of the 1960s and '70s, aided and abetted by scientific advances like the birth control pill, which decoupled sex from reproduction and turned it into recreation pure and simple. High school kids got their vocabularies stretched as elders accused them of being "promiscuous." They looked it up and smiled. "Sure," they said, "why not?"
Half a century later, kids are still shocking and elders still shocked, but for shockingly different reasons. Lately it is youthful indifference to sex that has parents scratching their heads. Promiscuity? Pockets of it remain, but the dominant response to the subject among Japanese teens, it seems, is the verbal yawn, "Mendokusai," roughly translatable as "What a nuisance."