Evidence against

In 2001 Kirby¹ found that, of 28 sex education programmes in the US and Canada aimed at reducing teen pregnancy and STIs, including HIV, none of the three abstinence-only programmes that met inclusion criteria for review were effective in delaying sexual debut. Furthermore, these three programmes did not reduce the frequency of sex or the number of partners among those students who had ever had sex.

However, this same review found that nine abstinence-plus programmes (meaning abstinence education as part of comprehensive sex education) showed efficacy in delaying sexual debut, as well as reducing the frequency of intercourse and increasing condom use once sex began.

In 2007, a second review by the same researchers of 56 programmes² found encouraging signs as a result of sex education progammes in the US and Canada in general. They found that “the percentage of sex and STD/HIV education programs with positive effects on behavior continues to increase and the strength of their evidence has also increased”. However, they had no reason to change their conclusions on abstinence-specific programmes. They said:

“Several abstinence programs, including abstinence-until-marriage programs, have been rigorously [emphasis in original] evaluated in experimental studies with large samples and found to have no overall impact on delay of initiation of sex, age of initiation of sex, return to abstinence, number of sexual partners, or use of condoms or other contraceptives.”

The same year, the Oxford University-based Centre for Evidence-Based Intervention published a meta-review³ of 13 US trials of abstinence-only programmes, enrolling about 15,940 young people in total (they had searched for trials of abstinence-only programmes in other high income countries, but had not found any).

They found that, compared with various controls, no programme affected the incidence of unprotected vaginal sex, number of partners, condom use, or sexual initiation. Only five of the 13 programmes measured the biological outcome of pregnancy rates and only four measured STI rates. Of these, one found a statistically significant fourfold increase in STIs amongst people who participated in abstinence-only programmes (p= 0.03), and one a twofold increase in the risk of pregnancy (p = 0.02). On the other hand, just one abstinence-only programme produced a significant 47% decrease in the rate of recent sex (protected or otherwise) in participants, and that only in the last month (p= 0.04).

In April 2007 the Princeton-based body Mathematica Policy Research produced a report⁴ evaluating four specific abstinence-only-until-marriage programmes. These programmes were intensive and started with children before the age they became sexually active.

They conducted a randomised controlled study of these four programmes, enrolling a total of 2057 children in the study and randomising 1209 to the programmes and 848 to receive nothing other than biological information about sex. Then they waited for four to six years after the young people started participating in the programmes. At this point, when the youngest participant would be 12 years old and the oldest 20, they examined the impact the programmes had made on sexual abstinence, unprotected sex, number of sexual partners, and knowledge about STIs, pregnancy and condoms.

Strikingly, the programmes made absolutely no difference whatsoever to the eventual sex lives of the participants. There was hardly a percentage point difference between the intervention and control groups on any measure of effectiveness. To give two examples: 49% of young people who had participated in the programmes had remained sexually abstinent – as had 49% who had not. Twenty-one per cent who had participated in the programmes had had unprotected sex in the previous twelve months – as had 21% who had not.

Programme participants were 2% better at identifying particular STIs than controls – and because of the sample size, this was statistically significant. Apart from this, the only significant difference between programme participants and control students was that more programme participants were likely to believe something untrue. For instance, 21% of programme participants agreed with the statement that “condoms never prevent HIV” compared with 17% of controls. Twenty per cent believed they did not stop gonorrhoea or chlamydia either, compared with 14% of controls.