Background
Early sexual initiation and inadequate contraceptive use can place adolescents at increased risk of unplanned pregnancy and sexually transmitted infections. These behaviours are patterned by gender and may be linked to social inequalities. This paper examines trends in sexual initiation and contraceptive use by gender and family affluence for Scottish adolescents.

Methods
Cross-sectional data from four nationally-representative survey cycles (2002, 2004, 2010, 2014) (n= 8,895) (mean age = 15.57) were analysed. Logistic regressions examined the impact of survey year on sexual initiation, condom use and birth control pill use at last sex; as well as any changes over time in association between family affluence and the three sexual behaviours. Analyses were stratified by gender.

Results
Between 2002 and 2014, adolescent males and females became less likely to report having had sex. Low family affluence females were more likely to have had sex than high family affluence females, and this relationship did not change over time. Condom use at last sex was reported less by males since 2002, and by females since 2006. Low family affluence males and females were less likely to use condoms than high family affluence participants, and these relationships did not change over time. There were no effects of time or family affluence for birth control pill use.

Conclusion
There has been a reduction in the proportion of 15-year olds in Scotland who have ever had sex, but also a decrease in condom use for this group. Economic inequalities persist for sexual initiation and condom use.