Teenage fertility rates in the UK are amongst the highest in Europe and have not altered significantly in the last 15 years, but the proportion of births outside marriage has risen rapidly. In this study we used longitudinal data from the National Child Development Study (NCDS) to investigate the social, economic and educational backgrounds of young parents. The analysis showed there to be striking variations in the probabilities of becoming young parents but not with respect to whether the child was born within or outside marriage. Young mothers and fathers were more likely to come from economically disadvantaged families and to have lower educational attainment. Teenage mothers were more likely to have mothers who had a child in her teens and were more likely to have exhibited higher levels of emotional problems particularly in adolescence. Young women whose educational attainment scores deteriorated between childhood and adolescence had particularly high probabilities of becoming young mothers. For some teenage motherhood was unintended and the result of unprotected intercourse whilst other men and women who subsequently become young parents had expressed a preference for early parenthood whilst still at school.