Teenagers will not refrain from having sex, even if you spend a billion dollars trying to persuade them to keep their trousers zipped and chastity belts locked.

This is the conclusion from a six year study by Mathematica Policy Research into the sexual behaviour of more than 2,000 teenagers across four states, and a variety of social groups.

The average age at which the teens reported having sex for the first time was identical: 14.9 years.

Neither group showed more inclination than the other to use contraception, either. Of those who said they'd had sex in the last year, 23 per cent in both groups said they always used a condom, 17 per cent only sometimes using a condom, and four per cent never did.

The number of partners was the same, too, with a quarter of teenagers in both groups reporting having had at least three sexual partners.

The abstinence programme has been a central part of the Bush administration's social policy, and the government has poured about a billion dollars into it over the last 10 years.

But the research would seem to suggest that the money has not been well spent. All that has happened is that teenagers are pledging not to have sex, getting their nice little silver rings, and then shagging like rabbits anyway. ®

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