It began as a low-key campaign among conservative Christians to discourage their children from having sex. Last week the abstinence movement emerged as a key plank of President George W. Bush's reform of American welfare policy.
As Bush extolled the virtues of abstinence as a protection against sexually transmitted disease and teenage pregnancy, congressional hearings opened on government plans to spend millions of dollars promoting the 'no sex is safe sex' campaign.
But as abstinence becomes a cornerstone of US social policy, it has opened up a bitter debate among policymakers. Many argue that it endangers sex education for young people, who will be sexually active anyway.
On the other side, supporters of the movement are organizing 'virgin pledges' in schools, claiming that they can delay teen sexual activity by up to 18 months.
In a speech in South Dakota last Wednesday, President Bush reiterated an election promise to spend as much on programs that teach abstinence until marriage as on medical services that provide contraceptives to teenagers.
Last February, the President laid out a budget for next year that would raise federal spending on 'abstinence only' education by $33 million (£23m), to $135m. Last week, this budget entered its phase of seeking congressional approval.
The arguments propelling the initiative are, ostensibly, medical not moral. 'Abstinence is the surest way,' said Bush, introducing a welfare reform plan, 'and the only completely effective way to prevent unwanted pregnancies and sexually transmitted disease.'
Such issues remain a huge problem for American teenagers. By the time they graduate from high school, two-thirds of the nation's young people have had sexual intercourse, according to the Centers for Disease Control and Prevention. One in four sexually active teenagers contracts a sexually transmitted disease each year.
Bush is under fire from his conservative Right over a number of issues, from the Middle East to immigration, and there is no safer place to satisfy it than on moral high ground it holds dear.
But the debate has also engaged leading think-tanks such as as the Brookings Institution, whose senior researcher Belle Sawhill told the Washington Post: 'There is some merit in promoting abstinence, but it is also the case that there are going to be kids, no matter what adults tell them, who are going to be sexually active.'
On the other side, the conservative Heritage Foundation is claiming that 'virgin pledges' and school classes recommending abstinence not only delay sexual activity but make a qualitative difference to young people's relationships.
The sexual abstinence campaign comes amid an atmosphere of growing intolerance towards the liberal presumption that teenagers will have sex, and that education's role is to make their activities as safe as possible, physically and emotionally.
In the recently published Harmful to Minors, Judith Levine writes: 'In America today, it is nearly impossible to publish a book that says children and teenagers can have sexual pleasure and be safe too.'
Harmful to Minors was rejected by many major publishing houses; one editor called the contents 'radioactive', another said the timing 'couldn't possibly be worse'; another asked her to remove the word 'pleasure' from her introduction. And once the book was finally commissioned by the University of Minnesota Press, it became the target of a campaign spearheaded by the conservative Right to keep it from being published altogether.
Talk show host Dr Laura Schlessinger denounced Levine as another in a long line of 'academic pedophiles', trying to make child sex acceptable. Robert Knight, director of the Culture and Family Institute, branded the book 'very evil'.
But many academic studies on the subject, including a recent report by former US Surgeon General David Satcher, argue that the only proven method for reducing pregnancy and sexually transmitted disease is to combine the abstinence message with one that teaches young people how to protect themselves. The Institute of Medicine published a report in 2000 concluding that abstinence-only programs constituted 'poor fiscal and public health policy'.
'There is no scientific evidence that "abstinence-only until marriage" programs work,' wrote James Greenwood, a Republican representative, to the President. Greenwood is co-sponsor of legislation to rival the President's program, seeking $100m for mixed education that 'teaches both abstinence and contraception from both a values and a public health perspective'.
Deborah Roffman, a sex education teacher in Baltimore and author of Sex and Sensibility: The Thinking Parent's Guide to Talking About Sex, said: 'The abstinence-only approach is not realistic. Fifty per cent of kids have already had intercourse.
'There is absolutely nothing wrong with a strong abstinence message, but to say it is the only option is culturally inappropriate because of the kind of environment we are raising our children in.'
The abstinence movement is carried by groups such as 'Free Teens', whose founder Richard Panzer organizes 'pledge groups' - in this case funded by the state of New Jersey. 'We work with the public schools to teach there are a lot of practical reasons to not have sex,' Panzer said. 'It is not just the medical side.'
One recent study showed that signing a pledge has some impact on teens. Columbia University sociologist Peter Bearman interviewed 20,000 teenagers and found that teens who took abstinence pledges waited significantly longer - on average 18 months - to have sex for the first time than those who did not.
'What makes a difference is that kids feel they are doing something special,' Bearman said. 'By pledging, they have an important sense of identity, and belong to an elite moral community.'
© Guardian Newspapers Limited 2002