Based on previous findings by Biehl et al., (2007) we hypothesised that earlier pubertal timing would be associated with increased cigarette and alcohol use. We regarded tests of the relationship between pubertal timing and parent-child relationship quality as exploratory based on inconsistent findings supportive of either early timing or off-time effects on adolescents experience of relationship quality with parents. Second, we hypothesised that there would be reciprocal links between poor parent-child relationship quality and cigarette and alcohol use over and above stability in these constructs across time. Following the contextual amplification hypothesis (Ge et al., 2002), our third hypothesis was that the relationship between poor parent-child relationship quality and later cigarette and alcohol use would be significantly stronger for early maturing children. Thirdly, we were also interested to examine the possibility of gender differences in the pattern of relations between parent-child relations, pubertal timing and substance use. Given that previous work does not support directional hypotheses of different associations for boys and girls, we regarded tests of the moderating role of child gender as exploratory.
