There is a surprising gap in the economic literature on social capital. First, we lack studies addressing the effects of social capital on those facets of development that can contribute in making growth more sustainable in the long run, like, for example, human development and social cohesion. Second, it is still unclear what type of networks may exert a positive effect on the different dimensions of development. In particular, the literature has not yet provided a rigorous assessment of the role of strong family ties, that are generally referred to as a form of bonding social capital causing backwardness. This paper carries out an empirical investigation into the relationship between the three types of social capital so far identified by the literature (i.e. bonding, bridging and linking), human development, and labour precariousness, in the belief that precariousness and uncertainty play a crucial role in determining the social cohesion and well-being that are necessary to make growth sustainable in the long run.