Adult-child sex and parental authority
One standard reason for morally condemning adult-child sex is that children are incapable of giving valid consent to sex with adults. In recent years this argument has been contested by several authors (Ehman, Kershnar and Leahy). Their counter-argument is that if the child's incapacity to give valid consent is the wrong-making characteristic of adult-child sex, other adult-child interactions that have precisely the same characteristic should be deemed morally wrong too, whereas in fact we regard many of those interactions as perfectly morally legitimate if not morally required.
After having explained the standard argument and its counter-argument more fully, I will try to assess these arguments by (i) introducing a morally relevant distinction between two classes of adult-child sex - namely, cases in which the adult involved either has parental authority over the child or is authorized to have sex with the child by those with parental authority, and cases in which the participating adult lacks these characteristics, and (ii) showing that the counter-argument is successful with regard to the former class of adult-child sex only - and, therefore, that the standard argument is basically sound with respect to the latter class. Next, I will argue that cases of the former class of adult-child sex should be morally evaluated in terms of the parental duty to look after the child's interests: if such cases should be considered morally wrong, the justifying reason is not the child's inability to give valid consent but their incompatibility with conscientious parenthood.
source: Lecture 'Adult-Child Sex and Parental Authority' by Jan Willem Steutel (Professor of Philosophy of Education); University of Amsterdam; Lecture: 20 February 2008