"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."