Does teenage childbearing increase smoking, drinking and body size?

This paper analyses the causal effect of teenage childbearing on smoking, drinking and body size using a sample of Australian twins and their relatives. Fixed effects estimates on samples of siblings, all twin pairs and identical twin pairs show that teenage mothers smoke more during their lives. Teen mothers tend to have a higher probability of being overweight, especially if they are older than 40 years. Their spouses are more likely to smoke and drink more. The quality of the spouse seems to be an important mechanism through which teenage childbearing affects subsequent maternal health.