I just want to note something here. I've recently heard some people questioning whether the informed consent argument is valid in the context of adult/child sex at all. The best way to see this is to consider any other issue of consent involving children. For example, performing surgery on a child. By the sexual consent rule, this would be child abuse in any circumstance. Similarly, defending legal rights on behalf of a child would be strictly prohibited and always abuse. If nothing else, these absurd consequences certainly show that there are exceptions to the informed consent rule that need explaining.

A common response is to suggest that these things are exceptions as they are "necessary". But in fact this is entirely inadequate: neither of these examples need be necessary - they could very well be merely "nice to have". Necessary actions surely are exceptions, but do not constitute all of them. A better response seems to be that an exception arises if an action is "responsible". to do. If doing the action is responsible then surely it should also be an exception? Necessary actions are exceptions because they are the class of actions that are responsible to do but irresponsible not to do. (i.e. they are "necessary" because not only is it OK to do them, but there is a duty to do them). But this still leaves the class of actions that is responsible either way.

Let's briefly explore the consequences for sex. According to this theory, it is OK for an adult to have responsible sex with a child, but not irresponsible sex. How can we make this judgment? Well, willingness surely plays a part; to have sex with an unwilling child is certainly irresponsible and thus always wrong. To have sex with a willing child may or may not be wrong depending on whether it would cause harm to the child, depending on which sexual acts were performed, depending on the protection worn and so on. It's interesting to note that this theory effectively passes the reigns to science: it is the job of science to determine whether children are or are not intrinsically harmed by sex, and the resulting ethical status of adult/child sex turns not on abstract ethical arguments, but hard, empirical investigation.