VALPARAISO | Programs that focus exclusively on abstinence have not been shown to affect teenager sexual behavior, although they are eligible for tens of millions of dollars in federal grants, according to a study released Wednesday by a nonpartisan group that seeks to reduce teen pregnancies.

"At present there does not exist any strong evidence that any abstinence program delays the initiation of sex, hastens the return to abstinence or reduces the number of sexual partners" among teenagers, the study concluded.

The report, which was based on a review of research into teenager sexual behavior, was released by the National Campaign to Prevent Teen and Unplanned Pregnancy.

The findings were disputed Wednesday by the National Abstinence Education Association, which said the study "entirely misrepresents the abstinence education approach," demonstrates an alarming bias and gives the medically inaccurate impression that condoms result in safe sex.

William Willard, cofounder of the regional abstinence-based program, A Positive Approach to Teen Health, declined to address the study directly, but defended her group's efforts in 50 Northwest Indiana schools.

"Our formal and informal evaluation results in teens making informed decisions about their health and futures," she wrote in a prepared statement.

Willard and NAEA referred to other studies upholding the effectiveness of abstinence education.

The regional PATH program was recently awarded $600,000 in federal funds to continue its efforts through the next year, Willard said. This is an increase from the $469,266 in federal funding the group received during each of the last three years.

Millions of dollars in federal assistance are at stake in the debate over the effectiveness of abstinence-based programs.

A spending bill before Congress for the Department of Health and Human Services would provide $141 million in assistance for community-based, abstinence-only sex education programs, $4 million more than what President Bush had requested.

The NCPTUP study found that while abstinence-only efforts appear to have little positive impact, more comprehensive sex education programs were having "positive outcomes."

The study also challenges the validity of claims by abstinence-only advocates that comprehensive sex education promotes promiscuity, hastens the initiative of sex or increases its frequency, and sends a confusing message to adolescents.

The Associated Press contributed to this story.