That evidence includes two independent reports that abstinence-only programs have no effect on teenage sexual activity and do not meet a basic scientific standard. These studies have led to a growing momentum in Congress to eliminate abstinence-only funding.

But instead of analyzing these studies, a four-hour hearing by the House Committee on Oversight and Government Reform rarely moved beyond championing the value of pre-marital abstinence. The discussion played into the central tenant of abstinence-only education: only abstinence, not condoms or contraception, can prevent sexually transmitted diseases and unwanted pregnancies.

The hearing showed that social conservatives continue to shape the public debate on this. Abstinence-only education, one plank of Newt Gingrich's 1994 "Contract With America," is now a big part of the Bush administration's public-health agenda, receiving $1.3 billion since 1997. Despite the current calls to end funding, the conservatives who framed the abstinence-only policy have created a formidable obstacle for opponents to overcome.

"It's going to be hard to make inroads," said Heather Boonstar, a senior fellow at the Guttmacher Public Policy Institute, an organization that conducts sexual health research. "Social conservatives are going to fight it tooth and nail."

The oversight hearing looked like the next step toward ending a program that only discusses condoms and contraception in terms of their failure rates, and teaches, "A mutually faithful monogamous relationship in the context of marriage is the expected standard of sexual activity."

The effort to end it gained steam after a 2006 Government Accountability Office report on abstinence-only programs, funded by the federal government's Dept. of Health and Human Services. GAO, an auditing arm of Congress, found that the programs were exempt from the HHS's usual requirement that its programs must give medically accurate information about condoms. In addition, the three abstinence programs studied weren't producing clear results and lacked any self-evaluation for success.

Last April, the Dept. of Health and Human Services-funded Mathematica Policy Research Group did its own evaluation of abstinence education. Beginning in 1997, when the federal government first gave states a total of $50 million toward abstinence-only education, Mathematica researchers followed students in four abstinence-only programs. They found that "abstinence-only programs had no effect on the sexual abstinence of youth."

Since Mathematica's findings, 17 states have said no to federal abstinence-only money. "Forty-two percent of teens now live in states that have turned down funding," Guttmacher said.

But the $50 million to state government's is only part of the $176 million in this year's federal budget for abstinence-only education. Of that money, $113 million is federal grants given directly to Community Based Abstinence Education, or CBAE, programs.

Following the reports, congressional Democrats have pushed to eliminate this money. But Rep. David Obey (D-Wis.), chairman of the House Appropriations Committee, kept the program in this year's health spending bill, saying it would make President George W. Bush less inclined to veto programs Democrats wanted -- like reproductive health clinics. "Abstinence-only was in jeopardy," said Ron Haskins, co-director of the Brookings Institution Center on Children and Families. "But Obey cut a deal."

Last month, 76 House members wrote to Obey, urging him to expend political capital on eliminating the state and CBAE programs from next year's budget. "Our tax dollars should be used to fund programs that benefit the public good," wrote Rep. James Moran (D-Va.), "not on unsuccessful, ideologically driven boondoggles."

A group of legislators, including Rep. Christopher Shays (R-Conn.), have introduced the Responsible Education About Life or REAL Act. It would move abstinence-only education dollars to abstinence-plus, or comprehensive sex-education. These would emphasize that abstinence is the sure way to prevent STD's and pregnancy, but would also explain the use of condoms and other contraceptives.

Shays, the last New England white shoe Republican in the House, tried to explain his position on Wednesday. "Sometimes I think we're trying to repeal the laws of gravity here," Shays said Wednesday. "There are natural instincts that young people will have and the REAL Act provides medically accurate information about both safe sex and contraception."

But despite the reports and the shifting political winds, his GOP colleagues refused to see the debate as one about medical accuracy. "This is a deep disagreement among competing values," said Rep. Mark Souder (R-Ind.). "Abstinence-only education is the only holistic approach to teach about the distressing elements of premarital sex."

Rather than ignore these emotional appeals, comprehensive sex-education proponents spent much of the hearing trying to prove they are pro-abstinence. "There is a broad consensus," Rep. Henry A. Waxman, the committee chairman, said in his opening statement, "that the benefits of abstinence should be part of any sex-education effort."

The concession that the federal government should value abstinence seemed to enable conservatives to stick with their tried-and-true logic. "There is no more scientific fact," said Rep. Virginia Foxx (R-N.C.), "that abstinence is the only way to prevent STD's and pregnancy."

Foxx and other social conservative's uncompromising stance gained traction in 1994, when the Republicans took control of Congress. Gingrich, as House Speaker, emphasized abstinence-only laws as a way to reduce the number of out-of-wedlock teenage mothers. The Republican Congress slipped $50 million for abstinence education into the 1996 Welfare Reform Act, after the bill had passed the House and Senate.

The provision laid out clear eight-point or "A-H" guidelines of what must be taught in order to receive funding. These include assertions like, "Sexual activity outside of the context of marriage is likely to have harmful psychological and physical effects."

Abstinence funding increased by $13 million in 1999, when Congress created the CBAE federal grants. The grants then grew exponentially under the Bush administration, going from $20 million in 2001, to its current level of $113 million in 2005.

Marcella Howell, a vice-president for Advocates for Youth, a nonprofit organization devoted to sex education, said abstinence education was an early priority of Bush's social agenda. "He kept saying during the 2000 presidential campaign he was going to triple abstinence funding," Howell said. "It was a component of his faith-based initiatives."

With Bush on his way out, Howell said that prioritizing abstinence education might be as well. "Democrats on the appropriations committee may feel enough pressure to eliminate the program," Howell said. But Howell added that for the funding to end, the debate must shift away from conservative ideology and toward accurate information.

On Wednesday, Rep. Jack Welch (D-Mass.) offered a brief glimpse of one such discussion. "The GAO when they do this report is a neutral arbiter," Welch said. "And the GAO has concluded these abstinence-only programs are not achieving results."