A key characteristic of debates on caring for children has been the distinction made between the public and the private or formal and informal sector of care. In particular, the impact on adult relationships of the material, emotional and moral dimensions of this division has been highlighted. What are the implications for children, however, of regarding the child care arrangements made by adults as private affairs between parent and provider? This paper reviews research on childminding registration to assess whether a similar system would regulate private fostering arrangements and thereby protect a hitherto neglected group of vulnerable children, private foster children.