It is very important to note that debates about research into the effectiveness of different types of sex education, and criticisms of the extent to which programmes contain factual inaccuracies and are guilty of stereotyping, do not always represent objective attempts to weigh the evidence that these studies have produced.

While the debate between supporters of both approaches has populated these areas of difference it is not in pursuit of a resolution of their differences but rather a definitive answer that suits their moral agenda.

There is no doubt that, whatever evidence is assembled, people who hold particular strong moral views are unlikely to give up supporting their preferred approach regardless of whether it works or whether someone else thinks it presents a distorted picture of the facts.

In April 2007 the results were published of a Congressionally mandated evaluation of federally funded abstinence based programmes in American schools.

The investigation, which looked at four programmes offering a range of settings and strategies, found that rates of abstinence and unprotected sex in students who took part in the programmes were virtually identical to rates among students who had been randomly assigned to not take part.

The ages at first sexual intercourse were also nearly identical, as were the numbers of sexual partners.

It appears that the programmes (abstinence or comprehensive) had no impact on how the students behaved.

With regards to HIV prevention, a systematic review of all relevant studies concluded, "Evidence does not indicate that abstinence only interventions effectively decrease or exacerbate HIV risk among participants in high-income countries; trials suggest that all the programs are ineffective in influencing behavior."