It would be discriminatory to allow same sex marriage between siblings but not opposite sex marriage between siblings, therefore an argument can be made against same sex sibling marriages on the basis of genetic defects in future generations.

Most importantly as I also explained again in one of my responses to yourself preventing same sex marriage effectively bars gay people from marriage. There is (as far as I'm aware) no individual solely attracted to their siblings in the same way that gay people are solely attracted to members of the same sex therefore denying marriage to siblings is not the same thing as denying marriage to same sex couples as the latter prevents an entire group from being married whereas the former does not.

Dally and Kirkstaller, a.k.a. Roy Ashburn and Keith O'Brien.

You sound like a playground bully calling people gay as if it's offensive.

If you really got that from what I posted, you are even more stupid than I had previously suspected.

If you listen, you might hear the woooshing sound overhead.