Brian Lee Reed, 30, and Marilyn Renee Lee, 36, have been arrested for having consensual sex. The problem is not the sex but the fact that Marilyn is the half-sister of Brian. The case could raise some interesting legal questions.

I have long been a critic of criminalization of polygamy, here and other moral legislation prohibiting such things as fornication or adultery.

Incest is an interesting legal question. The moral claim against incest is constitutionally suspect. People have the right to follow different moral constructs and guidance. The public policy claim was based on genetic abnormalities. However, some couples may not be able to conceive or use protection to avoid conception. Moreover, the medical case for such dangers may not be higher with a half-brother or half-sister than the population at large. A recent study shows that, at least with cousins (who are covered by these laws), there is no greater risk for such defects. Indeed, some researchers have recommended decriminalizing incestuous sex, here.

The point is that the state should bear the burden of proving such a connection. Even assuming that the state does not have to show that it is the least restrictive means, a rational basis test still demands some connection. The Supreme Court ruled that states cannot criminalize homosexual relations in Lawrence v. Texas.

Under state law, “[p]ersons being within the degrees of consanguinity within which marriages are declared by law to be incestuous and void, who intermarry with each other, or who commit fornication or adultery with each other.” What is particularly remarkable is the maximum sentence for incest in Idaho: life in prison. That seems completely out of scale with the offense and driven by the moral rather than public policy rationale. Obviously, the case is stronger with siblings than cousins. This is a taboo subject, obviously, and the notion of incest is offensive to most of us. However, from a constitutional standpoint, we need to separate our personal opposition from the scientific basis for the criminalization.

There is also some research on the attraction of siblings who are raised separately. It is called “genetic sexual attraction.” The opposite appears to occur with the “Westermarck effect” when siblings are raised together in close proximity.

Reed is no stranger to sex offenses. He was already in jail for violating probation in connection to a 2002 conviction for sexual battery involving a minor.

For the full story, click here.