If it takes place solely between consenting adults, then the law have no business regulating it.
Of course, procreation ultimately doesn't take place solely between consenting adults, so there's an argument for criminalizing incestuous breeding. But since sex and pregnancy aren't linked anymore, sexual relationships - especially those from which no offspring can result anyway, like same sex relationships - shouldn't be banned.
One could perhaps make sterilization a requirement for the legality of the heterosexual ones though. But that's such an intensive invasion of an individual's personal life, so probably better to simply outlaw incestuous procreation, and punish those then do so anyway (which is usually the only way these kinds of relationships are discovered by the authorities anyway, so it'd make for a far more enforceable law as well).
Generally, it takes some pretty fucked up internal psychological conditions and/or external environmental conditions to want to bed your brother/sister/father etc., but human sexuality have tons of bizarre outlets, and as long as they take place only between consenting adults, then banning them should be out of the question.
If you want to counter this stuff (or rather the social instability which is frequently, but not always, behind it), more extensive social services to support unstable families, and access to free mental health care, would be the way to go. Unlike some unenforceable ban, those measures might also actually work to reduce it.
Of course, procreation ultimately doesn't take place solely between consenting adults, so there's an argument for criminalizing incestuous breeding. But since sex and pregnancy aren't linked anymore, sexual relationships - especially those from which no offspring can result anyway, like same sex relationships - shouldn't be banned.
One could perhaps make sterilization a requirement for the legality of the heterosexual ones though. But that's such an intensive invasion of an individual's personal life, so probably better to simply outlaw incestuous procreation, and punish those then do so anyway (which is usually the only way these kinds of relationships are discovered by the authorities anyway, so it'd make for a far more enforceable law as well).
Generally, it takes some pretty fucked up internal psychological conditions and/or external environmental conditions to want to bed your brother/sister/father etc., but human sexuality have tons of bizarre outlets, and as long as they take place only between consenting adults, then banning them should be out of the question.
If you want to counter this stuff (or rather the social instability which is frequently, but not always, behind it), more extensive social services to support unstable families, and access to free mental health care, would be the way to go. Unlike some unenforceable ban, those measures might also actually work to reduce it.