Sexual debut for boys in Kenya occurs mostly by mid-adolescence. This study looks at the perspectives of adolescent boys aged 15–19 attending schools in rural, eastern Kenya on the dual risks of unwanted pregnancy, STDs and HIV, based on qualitative data from eight focus group discussions with 90 boys. Despite a high knowledge of sexual risks, fear of HIV and awareness of the protective value of condoms, the young men exhibit high risk behaviour. They feel the need to conform to social prescriptions of male prowess, early sexual experience, and having more than one partner, yet their feelings about this behaviour are ambiguous and contradictory. They consider getting girls pregnant and having had a treatable STD as marks of masculinity, blame girls for not protecting themselves (and girls' parents), and want to boast about their sexual conquests to their peers. Yet they feel embarrassed and reticent about discussing sexual issues with adults, and are unwilling to get condoms from places where anonymity is not assured as they know their sexual activity is not sanctioned. There is a clear need for educational programmes that confront male sexual norms, address issues of gender power relations, promote communication skills, informed choice and sexual responsibility among boys as well as girls, and provide a consistent supply of good quality condoms free or at affordable prices.