I guess before I can debate this further with you, you will need to define what 'virtue' is and what 'corrupting effect' sex has on a person (regardless of their sex, unless you hold males and females to a double standard when it comes to sex). Assuming that person X truly desires to be killed and eaten alive (presumably not in that order), and is not coerced into this activity, and is not suffering from some mental illness causing them to be incapable of consenting to such a thing, I find it to not be immoral if they are killed and eaten alive. The question comes down to capability of consent in either case, and I would argue that most 14 year olds are capable of consenting to sex. Sure I can accept your points that legality and social norms are irrelevant, indeed I claim that the current social norm of the USA forbidding sexual intercourse with most teenagers, and the fact that such intercourse has been illegal for the past hundred or so years, to be completely irrelevant to morality. Of course, the majority of people claim that it must be immoral because it is socially frowned upon and has been so for their entire lives. I can also agree that what we are biologically programmed to do is irrelevant to morality, after all men are biologically programmed to rape but it doesn't make rape moral.