An undue burden according to who?
Any state that believes that siblings should not marry, can of course change their laws to prevent same sex siblings from marrying if their current language is not gender blind. IF states choose not to do so- well apparently the states don't care.
Meanwhile- siblings are prevented marrying regardless of fertility in every state in the United States.
But First Cousins in many states are allowed to marry only if they can establish that they cannot procreate together.
Clearly procreation is not the basis for denying siblings from marrying.
And never was.
And Obergefel doesn't change any of that.
Either States had a valid reason before- and still do- or they didn't have a valid reason before- and still don't.
Meanwhile- you can go demand your day in court- for 'justice'
Iowa law restricts only opposite sex family members from marriage
Maryland only restricts those that vaginally penetrate.
Of course prior to Obergfell, neither state allowed any. It was due to Obergfell.
And if Iowa cares about siblings marrying- Iowa can change Iowa's law.
I don't even know what the hell you mean about Marylands law but you seem obsessed with sex...
Meanwhile- siblings are prevented marrying regardless of fertility in every state in the United States.
But First Cousins in many states are allowed to marry only if they can establish that they cannot procreate together.
Clearly procreation is not the basis for denying siblings from marrying.
And never was.
And Obergefel doesn't change any of that.
Either States had a valid reason before- and still do- or they didn't have a valid reason before- and still don't.
Meanwhile- you can go demand your day in court- for 'justice'