(April 20, 2015 at 12:56 pm)Mezmo! Wrote: ... The marriage partners cannot be blood relatives.
...
That isn't true. It is a question of how closely related the people are. But they may be related by blood. To get you started, see:
http://en.wikipedia.org/wiki/Cousin_marriage
As for gay marriage, it changes only one thing about a marriage, and that is the sex of the people who are getting married. It changes nothing else, or, at least, it need not change anything else, about marriage. This is conceptually an extremely simple change, and consequently you should have no trouble at all understanding it.
Frankly, I don't really believe that you have any trouble understanding this. If you did have trouble understanding it, you would be near brain-dead. It is so simple and easy to understand that you would have to be a total moron to have any trouble with the concept.
"A wise man ... proportions his belief to the evidence."
— David Hume, An Enquiry Concerning Human Understanding, Section X, Part I.