At the local level, parental responsibility now includes the task of holding corporations responsible for the foods foisted on children, an important new permutation of the old notion of in loco parentis.

NPR: Rabid Reader: 'Fat Land' and U.S. Supersizing

Ms MacCallum said the fact parental warmth and quality of parenting was similar in all three groups showed "it is the level of commitment to parenting that is important, and not the presence or absence of biological links between parent and children".

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