Congress is set to vote today on abstinence-only programs that have proliferated in the past five years.

President Bush favors an extension of funding for the programs. They were created as part of a massive 1996 welfare law. The programs bar any discussion of condoms or birth control _ other than to explain their limitations.

A study released yesterday says the programs have had trouble engaging parents and local schools. The report -- written by independent evaluators -- concludes there is no reliable evidence that the programs are effective in reducing teen sex, pregnancy or the transmission of disease.

Supporters say other programs promote sexual activity. Critics say abstinence-only doesn't provide teens with the information they need to protect themselves.