Young Americans who pledge to remain virgins until they marry have the same rates of sexually transmitted diseases as those who do not, a new study says.
The Bush administration backs the abstinence movement
Teenagers who take a public vow to abstain from sex have fewer partners and get married earlier.
But they are much less likely to use condoms, the research found.
"It's difficult to simultaneously prepare for sex and say you're not going to have sex," the study's author Peter Bearman told the AP news agency.
'Just say no'
The research, which is being presented at the National STD Conference in Philadelphia, examined the sex lives of 12,000 adolescents.
The data was gathered from young people aged 12 to 18 who were questioned again six years later.
According to the study, the STD rates were:
- Whites who pledged virginity 2.8% - did not 3.5%
- Blacks: pledgers 18.1% - non-pledgers 20.3%
- Asians: pledgers 10.5% - non-pledgers 5.6%
- Hispanics: pledgers 6.7% - non-pledgers 8.6%
The study's authors say that from a statistical point of view, the rates are the same for both groups.
"The message is really simple: 'Just say no' may work in the short-term but doesn't work in the long-term," Peter Bearman of Columbia University's Department of Sociology said.
Critics of abstinence-only education said the findings showed that adolescents benefit from sex education.
"It's a tragedy if we withhold from these kids information about how not to get STDs or not to get pregnant," Dorothy Mann, of the Family Planning Council, told the Associated Press.
But promoters of abstinence argue that telling young people about condoms and other forms of contraception increases sexual activity - and as a result increases the rate of teenage pregnancy and the transmission of sexual diseases.
US President George W Bush has massively increased funding and support for the US sexual abstinence movement during his term in office.
Christian abstinence organisation True Love Waits says it has more than one million card-carrying young members.
On 13 February, thousands of American teenagers celebrated a "Day of Purity" to promote sexual abstinence.