This paper examines how socio-economic changes in Tanzania have impacted on parent-child relationships, in particular parental behavioural control over their children and parental influence on young people's sexual behaviour. Data came from participant observation, focus group discussions and in-depth interviews with young people (14-24 years) and their parents. Socio-economic changes (education, changes in values, material needs provision) affected parent-young person relationships. Young people contributed to the economic needs of their families and parents receiving or expecting more support from their children exercised less behavioural control (in sexual and non-sexual matters of their children). Parents and young people spent less time together than in earlier generations. Parents reported that they thought their children were more knowledgeable about sexual and reproductive health than they were. As young people received more education and contributed more to their families' economic well being. they emerged as decision-makers in their own right and parental influence waned. Policy interventions addressing sexual and reproductive health among young people should consider family influence on young people as well as the influence of young people on their families and parental authority. Families, and particularly parents, should be supported to respond to the emerging challenges and changes in their families and the wider society.