If sexually transmitted diseases continue to increase among US teens, what is the point in spending millions of dollars on abstinence education, senators have begun to wonder.
Earlier this year the Center for Disease Control said one in four teenage girls had a sexually transmitted disease.
Also Planned Parenthood, a non-profit organization, estimates that two thirds of teenagers will have experienced sexual intercourse by the time they leave school.
And with some 750,000 teenage pregnancies a year, America has one of the highest teen birth rates in the developed world.
Clearly the abstinence only education programme seems to have had little impact on the target group.
"This national programme which has wasted $1.5bn (Ģ750m) of tax money is a failure and our teens are paying the price," says Cecile Richards, president of Planned Parenthood.
"We've been wasting money on programmes that don't work and we're seeing the consequences every single day."
Abstinence education ignores the fact that teenagers are sexually active and fails to give them accurate medical information or advice on safer sex.
"We get sex-ed classes in school and that should be where teens get the right information - but that isn't happening," says 15-year-old Mildred, from Arizona, who volunteers as a peer educator with the Planned Parenthood.
"They don't touch on subjects like sexuality, STDs (sexually transmitted diseases), birth control - it's not allowed because of abstinence-only education. It leaves you on a cliff-hanger - and a lot of teenagers become sexually active in their middle school years."
"Teens are curious and they want to experiment and if they know what's out there and they have the correct information, they're going to know how to protect themselves and prevent an unwanted pregnancy and an STD," adds Maryland high school student Melissa.
"Putting up a wall and saying 'don't have sex' makes them more curious and wanting to know what it is. But if you tell them the straight facts they're going to know how to protect themselves. It's about taking care of yourself."
At least 17 states have opted out of the system and others have suspended funding while Congress investigates whether such programmes work, reports Jane O'Brien of the BBC.
Critics say there is no evidence that they delay sexual activity and teenagers who have taken a vow of virginity are less likely to use protection if they break their promise.
But Roger Norman, a Texas lawyer and who runs an organization called Wonderful Days that teaches abstinence as part of the health curriculum in some local schools, says he is convinced that abstinence is the only way for kids. He himself doesn't receive any government funding and hence cannot be said to have any vested interest.
"You begin by teaching the consequences of bad behaviour and the benefits of proper behaviour and you do that in a way that a child can grasp.
"Self control leads to a happy, joyful life. If we can learn to control the most basic of drives - the sex drive - for good, then we can control drugs, gangs, alcohol and abusive anger."
His lessons promote marriage and virginity - for both partners - as an ideal.
They emphasise disease as a consequence of sex before marriage.
Some of his former students say that sexual abstinence is sensible and beneficial.
Eighteen-year-old Ashley says she believes teenagers who experiment with sex are laying the foundations for troubled relationships later in life.
"At some point everybody ends up getting married. Everybody wants commitment at some point and nobody likes to be cheated on."
Sixteen-year-old Josh says he relies on friends to help him stay abstinent.
"I have a lot of close friends and we pretty much agree on the same thing so we keep each other in line most of the time. Yes, it's difficult, but my friends are there and I'm there for them, and it gets easier if you have friends who agree with you."
"I'm pretty confident I can keep my abstinence vows," says 15-year-old Kirsten. "It was pretty hard reaching that decision, because living in this world today, it's almost expected of you to 'do it.' But with my religious upbringing and convictions and commonsense, it's really not that hard."
Teenagers who do have sex before marriage are given another chance by becoming "secondary virgins".
"Of course, if you view virginity as number one, and you've slept with someone, of course it's going to be different and you can never go back - but that doesn't mean there's no tomorrow," explains Ashley.
"Every day is a new decision and abstinence is not one you make once. You're going to have to make this decision over and over again. So if you fail once, you get back up and you try again."
The row over abstinence education is part of a much wider debate in the US about "family values".
Many conservatives are concerned that "American values" are being eroded.
But their opponents believe that the conservatives have an overly influential political voice, particularly within the current Bush administration.
For liberals, the campaign to roll back the abstinence programmes is part of a broader struggle against what they regard as reactionary elements in the US government.
Valerie Huber, chief executive of the National Abstinence Education Association, argues,
"Compare this with healthful eating. We know that obesity is rising in America. That doesn't mean though that we minimise the optimal health message."
"We still stress good eating habits, we still stress exercise, knowing that, unfortunately, many Americans are not going to listen."
If Congress does decide to cut government funding for abstinence programmes, they will still continue, it is felt, for other conservatives will pitch in.