An Inconsistency in the Law?

This blogger, who is no friend of marriage equality, had an interest in Will Saletan’s writing on the David Epstein case.

Hey Will, can you do an article on the procreation rights of fathers and daughters, as opposed to the naked/orgasm/screwing rights? (Well, perhaps you could look at those three separately too, since they are rather different.) For instance, would it be a crime for a daughter to impregnate herself with a vial of her father's sperm? Is it something we have to allow a father and daughter to do, if they wants to?

If I recall correctly, many states do not outlaw this, and it was used as a defense in at least one case in which in which a woman (or perhaps girl) was pregnant, perhaps by a stepfather. Pregnancy was no proof that they had actually had sex, and the laws were against the sexual contact, not conceiving together. Any state that does not have a law against two people conceiving together should not be able to use the “inbreeding causes birth defects” argument to keep consensual consanguineous sex illegal.