This research set out to explore sexual responsibility, experiences of fatherhood and constructions of masculinity among young men aged 17 to 25 years from socio-economically disadvantaged backgrounds in Ireland. The study was conducted against a backdrop of research that documents an important social-class dimension to sexual attitudes and behaviours. Lower socio-economic status and lower levels of education have been consistently associated with various indicators of risky sexual behaviour. Closely related to men’s sexual experiences is the possibility for men of becoming a father. Little research in Ireland has examined young men’s constructions of fatherhood, the influences on these constructions, or how men make the transition to fatherhood, especially following an unplanned pregnancy. This study seeks to address this gap.