Social capital has become an increasingly popular concept in policy discussions surrounding integration and social cohesion. Within the UK, numerous policy-makers have drawn heavily on the work of influential social capital theorist Robert Putnam, whose recent thinking has been implicated in debates concerning identity, diversity and cohesion. What is meant by 'diversity' is subject to conjecture. Arguably, identities and affiliations are more complex than often presented in social capital debates. Drawing on material from an ongoing longitudinal study, the paper addresses the relative neglect afforded to young people's networks and resources by focusing on the role many play in creating social capital within families. Acknowledging the significance of time and space, the paper explores the interface between different aspects of identity and the dynamic nature of social networks. In doing so, the need to take a more nuanced and context-sensitive approach to the analysis of social capital is highlighted.