I don't see what the sphincter has to do with consenting. Even if you arrive at the position that participating in anal sex is a health-hazard(which, if performed correctly, it isn't), that isn't a basis for calling the act unconsentual. For starters, hetero couples do it as well, and secondly, how many potentially hazardous activities are legal in this country? A lot.
I just think that's a weak argument. At least with the mental defect argument, there is a scientific foundation for that position(I mean, there are actually qualified people who have taken that side, and they actually have presented something resembling evidence to back up their theories), though I absolutely disagree with it. To my knowledge, that doesn't apply with your other argument.
Beyond that, I don't think we have anything else to argue on this subject. I understand your point of view, you seem to understand mine. I simply must agree to disagree in regards to homosexuality being a mental defect. That's certainly a vast improvement over fighting about things when we know we're not going to change the others' mind.
