The comments about the abstinence research evidence in your article on sex education are rather misleading (“Rise of the puritan classes”, 11 May). The 2009 Janet Rosenbaum study from Harvard did not look at school sex education programmes but evaluated religiously-based virginity pledges. Her findings also need to be considered in the light of the much misreported 2005 Bruckner and Bearman study from Columbia University. This also showed that virginity pledgers at youth meetings outside school settings (not receiving abstinence-focused education in schools) were less likely to use condoms when they eventually did have sex in their twenties. However, even so, this did not lead to a greater number of sexual infections. In fact, their STI rate was lower (although not statistically significantly so).

This and some other points notwithstanding, you are to be congratulated for your courage in even raising the possibility that, as your editorial suggests, there is an alternative to “serial shagging” as the best we can offer our students.

Dr Trevor Stammers, Senior lecturer in medical ethics and law, St Mary’s University College, Twickenham, London.