When Mad magazine did its parody of the movie “Grease” 35 years ago, there was a cartoon panel that showed Olivia Newton-John as the demure, preppy Sandy, surveying the obstacles to her love for John Travolta’s tough-guy Danny Zuko. “I love him,” she said, “And I’m going to do whatever it takes to keep him.” So she became . . . 

“A slut!” That was the next panel with the iconic leather-clad, tarted-up Sandy, who’s ready to vamp her way through “You’re the One That I Want.” Then she adds, “What a great message for the youth of America!”

Because I was 16 at the time, I had no objection to Newton-John becoming Totally Hot, as the album title of a few months later declared. Besides, even playing a high schooler, Newton-John was pretty well-established as a grownup by then. I don’t remember it causing adults any real consternation at the time, and it never stopped “Grease” from being watched incessantly by tweens during the next decade.

The cycle repeated itself a generation later when Britney Spears went up against the teen-pop backlash of the moment with the edgier “I’m a Slave 4 U,” then ratcheted up the outrage by kissing Madonna on TV. If Newton-John’s move was seen as an act of career calculation—the soft pop hits had slowed down before “Grease”—¬Britney’s was seen as career desperation. Then her personal life spiraled downward and the provocation didn’t just seem like pandering, but a cry for help.

But neither Britney nor her career collapsed. When she returned to radio stardom, it was with the sonic breakthrough of “Toxic,” a song that was for a grownup to sing, but not one drenched in controversy. That might have been a lesson going forth. Instead, since “Gimme More,” Britney’s niche has been the artist who says “bitch.” In Will.i.am’s “Scream & Shout,” it was in the hook. Now, it’s in the title.

And yes, this is leading to Miley Cyrus. Four years ago, she did a controversial Vanity Fair cover. Three years ago, she showed up on the Can’t Be Tamed album in black leather and a bra. The edgier title track was about the 80th song of its type and ran its course quickly. At the time, edgy Miley was considered one of the great career miscalculations. Cyrus’ teenage fan base was rejecting her new persona in favor of a still-relatable Taylor Swift, observers thought.

All that changed a month ago, when post-VMA references to twerking became as groan-inducing and unavoidable as jokes about bringing sexy back in 2006. Look at a screen full of tweets and one of them will likely be about Cyrus. (If not, you must not follow any radio stations.) Now, “Wrecking Ball” is sitting at No. 1 on the Billboard Hot 100 and the still from the video that goes with it is an instantly iconic pinup, the Cars’ Candy-O front cover for this generation.

Suddenly, Cyrus’ slightly clunky path to adulthood seems a little less desperate and a little more savvy. For the record, I am less troubled by what she does on TV than the notion that establishing yourself as an adult artist must include a reference to doing drugs in the bathroom. At least in the interim we were spared a song called “Hey, Kids! Smoking Is Cool!”

Now the ante is now upped for every female artist, especially for acts trying to break down radio's resistance to their earlier teen stardom. Swift, having already eroded her squeaky-clean image with songs about ex-boyfriends, declared herself “22” on her last album with relative subtlety (aside from the act of the song itself). Will that be enough next time? What does Katy Perry have planned for her next video?

Artists like Spears and Christina Aguilera who have already crossed the Rubicon are pretty much stuck there, until pop culture deems them too old to be acting all sexy—which is troubling in itself. Newton-John’s last semi-hit, “Soul Kiss,” was also her most explicit. But pop radio groaned, having already moved on to Madonna, who is now dismissed in the same way. We mock Janet Jackson’s ongoing references to S&M. For Rihanna, it was another great message for the youth of America.

No one wants to grow up to be a scold, and I would never begrudge subsequent generations their own leather-clad Sandy. Every generation survives the pop lyrics and culture that disturbs their elders. But it’s further evidence that the adult appeal of pop music now is happening because of its PG-13 rating, and not despite. And that provocation, for better or worse, is rarely a bad career strategy.