What kinds of obligations do parents have towards their children as family life becomes more complex? Many children pass through a number of different households, living with one or both parents, step-parents and step-siblings. The controversy surrounding the Child Support Act indicates that social norms do not yet sit easily with legal regulations. So how are new forms of family life accommodated in the legal system? This book argues that parenthood, rather than marriage, is now emerging as the central mechanism through which moral principles are converted into legal and social obligations.