Here's another conversation parents didn't know they had to have with their kids: Don't send nude photos of yourself out into cyberspace.
Too late. They are.
A survey of teens and young adults released last week reported that one in five teens - and a third of 20-somethings - have electronically sent or posted online nude or semi-nude pictures or video of themselves.
Even more - 40 percent of teens and 60 percent of young adults - are "sexting," sending raunchy messages via text, e-mail or instant message to each other.
More females do this stuff than males, but it is pretty close. Most often it is between boyfriend and girlfriend, but sometimes it is about letting someone know you are interested in hooking up.
Girls think it is flirty and fun, guys think it is hot, and they share it with their buddies. Everybody agrees that it ratchets up sexual expectations when the two parties meet in person.
And even the 20-somethings - who read People magazine and understand that naked pictures of yourself can come back to haunt you - aren't all that worried about a potential boss or a potential spouse or a potential Senate confirmation committee stumbling on these pictures on the Web.
"For anybody over 40, this kind of cyber-courtship is news," said Bill Albert, who is over 40 and chief program director of the National Campaign to Prevent Teen and Unplanned Pregnancy.
His organization worked with CosmoGirl.com to fund a survey of more than 1,200 teens (ages 13 to 19) and young adults (ages 20-26) for the report.
It wasn't news to Marisa Nightingale, senior adviser for the National Campaign. "Young people have been flirting and pushing the boundaries since the beginning of time," she said.
What surprised her, she said, was the fact that this very private stuff got passed around - a lot - and especially by the guys. "It was upsetting how many young people received them and passed them around," she said.
She was not surprised that it is more commonplace among young adults, who should know better. "This is not a youthful indiscretion," she said. "By the time they become young adults, it is more pervasive, more commonplace."
The problem is that, unlike love letters that can be tossed in the fireplace when the relationship is over, nothing in cyberspace ever really gets deleted.
A relationship goes south, and an aggrieved party can use those indiscreet photos and messages to hurt and humiliate. There are even Web sites just for the purpose of burning your ex.
OK. So now what?
"A parent's gut reaction will be to take away the cell phone and shut down the computer," said Albert. "But you can't blame the technology. It isn't going away."
However, a heart-to-heart conversation with your teen about why this might be a bad idea, about how these photos and messages live forever and can come back to bite you in ways you can't possibly imagine, isn't going to work, either, he said. "They know, and they are doing it anyway."
There are other ways to approach this, Albert and Nightingale said. And most are through the back door.
"The No. 2 reason girls - both teens and young adults - give for doing this is as a 'gift' to their boyfriend," Albert said. "I think you can have the conversation that this is not what we meant when we talked about female empowerment."
Rather than demonize the technology or use this as just another example of a generational divide that can never be bridged, said Nightingale, "it is an opportunity to ask what is the dividing line between public and private.
"We may find we are on very different pages," she said. "But it is an opportunity to ask the question and listen to the answers."
The conversation doesn't have to involve finger-wagging or threats. "You can say that you want to understand why people do this and ask what they think about people who do this," said Nightingale.
"It is an opportunity to be clear about your values. You can still tell a 25-year-old what you find objectionable. They may not think you care. How will they know what you think if you don't tell them?"
Albert - the over-40-year-old - wondered out loud if this was how his parents felt about Elvis. How could anybody move their hips like that with television cameras on them and the whole world watching?
"I don't want to sound prudish," he said. "Maybe in 10 years time this will be normalized."
Maybe in the not-to-distant future, he said, with regret in his voice, you won't be able to find a job applicant who doesn't have nude photos of himself out there on the Web.
Albert wondered what that might say about the value we place on relationships.
I wondered what that might say about the human race.