A congressional analysis of more than a dozen federally funded "abstinence-only programmes" unveiled a litany of "false, misleading and distorted information" in teaching materials after reviewing curriculums designed to prevent teenage pregnancy and sexually transmitted disease.

There are more than 100 abstinence programmes, involving several million children aged nine to 18, and running in 25 states since 1999. They are funded by the federal government to the tune of $170m (£88.5m), twice the amount when George Bush came to power.

The money goes to religious, civic and medical organisations as grants. To qualify they may only talk about types of contraception in terms of their failure rates, not about how to use them, or the possible benefits.

The survey was conducted by the staff of congressman Henry Waxman of California, a longstanding Democratic critic of the Republican administration's approach to sex education. His team concentrated on the 13 programmes that are most widely used, and found only two of them were accurate.

"It is absolutely vital that the health education provided to America's youth be scientifically and medically accurate," Mr Waxman said. "The abstinence-only programmes reviewed in this report fail to meet this standard."

Other "facts" include that abortion can lead to sterility and suicide, half the gay male teenagers in the US have tested positive for HIV, and condoms fail to prevent transmission of HIV in 31% of incidences of heterosexual intercourse. US government figures contradict all of these assertions.

AC Green's Game Plan - a programme named after a basketball player who said he would not have sex before marriage - teaches: "The popular claim that condoms help prevent the spread of STDs, is not supported by the data."

Mr Waxman told the Washington Post: "I don't think we ought to lie to our children about science. Something is seriously wrong when federal tax dollars are being used to mislead kids about basic health facts."

But government officials said Mr Waxman's report rehashed old anti-abstinence prejudices for political purposes. Alma Golden, the deputy assistant health and human services secretary for population affairs, said it took statements out of context to present programmes in the worst possible light.

"These issues have been raised before and discredited," Ms Golden said. "One thing is very clear for our children: abstaining from sex is the most effective means of preventing the sexual transmission of HIV, STDs, and preventing pregnancy."

Mr Waxman also criticised some programmes for reinforcing sexist stereotypes to children. One - Why Know - says: "Women gauge their happiness and judge their success by their relationships. Men's happiness and success hinge on their accomplishments."

Another programme, Wait Training, says: "Just as a woman needs to feel a man's devotion to her, a man has a primary need to feel a woman's admiration. To admire a man is to regard him with wonder, delight, and approval. A man feels admired when his unique characteristics and talents happily amaze her."