Abstract
Stephanie Sanders and her colleagues recently published an analysis of which behaviours were considered 'sex' in Sexual Health. They suggest that researchers and practitioners need to be aware of the variations in the definition of sex when taking sexual histories, conducting sex research or engaging in sex education. We agree that attention needs to be paid to what constitutes sex, lest people be incorrectly classified as having not had sex, or fail to recognise that health promotion messages are aimed at them. In particular, we suggest attention be paid to the ways in which gay men understand what constitutes sex.