Changes in sexual behaviours: from secular trends to public health policies.

Objective: To explore the relative contribution of secular trends and public health policies to changes in sexual behaviour.

Design: Three random probability surveys of the sexual behaviour of people aged 18-69 years were conducted in 1970, 1992 and 2006 in France.

Methods: Data of the 2006 survey (n = 12,364) were compared with those from two surveys carried out in 1970 (n = 2625) and 1992 (n = 20,055).