When Cooper Schwartz was 13, his parents were the last people on Earth he wanted to talk to about sex.
Given that his mother, Pepper Schwartz, is a sex educator and co-author of "Ten Talks Parents Must Have With Their Children About Sex and Character," sex had always been a subject for open discussion. But when he hit puberty, "it was 'anyone but you' for a few years," Pepper Schwartz said.
No one ever said that talking to your kids about sex was easy -- especially when the talk about the birds and bees turns to things like sexually transmitted diseases, birth control or masturbation -- but that's no excuse to put off the discussion, Schwartz says.
Two thirds of sons in the study said they had not talked with a parent about how to use a condom before they started having sex.
"It's sad to hear that so many parents [are] so far behind the curve," Schwartz said after hearing about the study. "Sex education is a lifelong thing [and parents] need to be able to pass on good information," even if they can't always be the messengers themselves.
When Cooper Schwartz said he wasn't comfortable talking to his parents, Pepper referred him to a few trusted male friends and said, "You have to have someone to talk to about this stuff." Cooper did turn to one of them, though within a year or so, he got over his embarrassment and began talking about sex with his mother again.
The study, published today in the journal Pediatrics, surveyed teens aged 13 to 17 on how sexually active they were and what sexual issues they had discussed with their parents. Their parents were also asked which sex talks they had had. Researchers repeated the surveys three, six, and 12 months later.
The researchers said many parents had missed the boat in educating their teens on sex.
When it came to protecting themselves against STDs, handling a partner who refuses to wear a condom, or even saying "no means no" when they weren't ready to have sex, many teens had already faced these issues on their own before their parents ever brought them up.
"I think parents today want to talk to kids but they don't know where to begin," said Dr. Mark Schuster, chief of general pediatrics at Children's Hospital Boston and a co-author of the study. He is also author of "Everything You Never Wanted Your Kids to Know About Sex (But Were Afraid They'd Ask)."
"They're afraid they'll make mistakes or don't know the facts, afraid to admit that their kids are growing up," said Schuster. "They avoid the topic altogether."
About one in four daughters in the study said their parents had not talked with them about how to resist pressure for sex. Two in five said that they had not discussed birth control or what to do if a partner refuses to use a condom "until after their sexual debut (if ever),"the authors wrote.
Though the study was small -- 141 parents -- and the researchers caution it may not be representative of all families nationwide, Schuster said these findings point to an important gap in communication for American parents.
"This was a study of parents who were motivated to talk to their kids about sex," Schuster said. All participants had also signed up to be part of a communication project caled Talking Parents.
"If we had had a representative sample of the country, I think we would have found that even more parents had not had these discussions."
So, when is the right time to talk to your teen about sex?
According to the experts, from day one. When they are toddlers.
"When they're bathing and they touch themselves, you give them a name for it, when they ask you questions as a child, you are open and responsive," said Schwartz.
"You don't wait for them to get sexually interested… then [they] think that it's [something] they could never ever ask their parents because it's too personal and embarrassing," Schwartz added.
Eli Coleman, academic chair of sexual health at the University of Minnesota Medical School, agrees. "We can never start talking too early -- [as long as] the discussion [is] age appropriate -- starting early makes further conversations easier and 'natural.'"
The traps that many parents fall into, says Coleman, are waiting too long and feeling that one "talk" fulfills a parent's responsibility.
"Nobody likes the big talk," Schuster agreed. "You forget things, you're nervous…it's more about us[ing] things as they come up…as a way for talking about sex, love, and respect."
And it's not about always having the perfect words of wisdom, Schwartz says.
"Don't sit there and preach…you don't have to give a finely crafted lecture. Ask questions, try to get a sense of their social world [and] let them know you are here to talk."
But as Schwartz will tell you, sometimes parents need a little help.
Her friend helped her son feel he had a confidant on sexual matters and Schuster agrees that this is "an excellent approach."
"If you're finding that there's no way to have a comfortable conversation with your kid…give license to another adult to have this conversation," Schuster said.
"It can be their minister, an uncle, their grandma, but it's your responsibility to make sure they do have someone to go to."
Educational books, school programs and discussions with the child's physician are all tools experts cite that help parents start and keep up the sex dialogue.
Ultimately, experts say, it's about bringing the sex talk out in the open, and making it a lifelong conversation.
"I think the 'what age' question is destructive in many ways," Schwartz said, because "the answer is: every age until you drop dead."