Despite increasing provision of school sex education, teenage sexual health in the United Kingdom is in overall decline, with increasing rates of terminations and sexually transmitted infections in under 18s outweighing recent modest reductions in conception rates in this age group.1 2 ^w1

Counterintuitively, rather than improving sexual health, sex behaviour interventions can make it worse.^w2 Most studies on sex education programmes in schools examine intermediate outcomes only, such as pupil satisfaction or reported condom use. This often facilitates premature false claims of success, whereas more robust outcome measures such as rates of terminations, unplanned conceptions, and sexually transmitted infections show no benefit.

In this week's BMJ Henderson and colleagues report the effect of a theoretically based teacher delivered sex education programme (SHARE) on registered conceptions and terminations.3 The trial found no significant difference between the intervention and control groups in National Health Service registered conceptions (per 1000 pupils: 300 SHARE v 274 control; difference 26, 95% confidence interval −33 to 86) or terminations (127 SHARE v 112 control; difference 15, −13 to 42) between ages 16 and 20.

The results should stimulate urgently needed change from …