The former, one of the reasons I raise incest is it is an example of the states being able to bar marriage between people, hence, arguments revolving around the states having no right to ban marriages are logically flawed. Arguments that the state should not possess that power are another matter, but as is, if someone states that no such right exist, they are overlooking precedent.




I should imagine we'd agree that 'messes' something might introduce into legislation aren't really good reasons to keep a ban on something.




That applies to polygamy pretty often too. Or, say, someone adopting an adolescent then marrying them when they turn 18, pretty foul but I don't think "grooming" can be a blanket reason, since it wouldn't apply to people of the same age (sibs/cousins) in all likelihood. Also, every state has different laws and qualifiers for incest, some allow first cousins. But yes, of course there's the genetic defect thing, but gay unions can't produce kids, so incest unions who agree not too breed would seem equally legit, and again their is an issue, is incest the only situation where a higher-than-average-probability of genetic defects bars marriage, should it be, should others be for that reason, etc.