To explore why teenage pregnancy is regarded by researchers from the USA and UK as a major social problem, a systematic review was conducted of published research on the social influences on teenage pregnancy. Papers published in the USA and UK between 1981 and 2000 were examined with respect to samples, social influences and outcomes. UK studies often justified investigating teenage pregnancy in terms of health. Research from the USA more often viewed teenage pregnancy as problematic because of associated welfare expenditure. A few studies from the USA regarded teenage parenting as mediating the intergenerational transmission of poverty. Such studies often focused on Black and minority ethnic populations. Most research considered economic and cultural influences, with a bias in research from the USA on cultural factors, and in the UK on economic factors. Overall, there were significant differences between research in the USA and UK. These may have arisen from a combination of political, religious and research design factors.