Rights is a political-philosophical concept adopted by our constitution (in mankind's greatest experiment in controlling the effect of the evil nature or potency of government power). The concept allows that all people have these rights by virtue of being born people. Some may have originally agreed with this precept for religious reasons, some might have for pragmatic purposes (having seen the uncontrolled nature of power). The point is they agreed and adopted a constitution to fit this belief and it is the belief itself which is the foundation for law and order.
You are free to believe that rights are derived solely from God, but our government is constrained to believe that the rights apply to all living human beings, as that is the law of the land. With respect to marriage - it may be more than a legal contrivance to religions and individuals - it is to me - but to the government it is a legal-admistrative merger that is used to deal with property / children distribution in the event of voluntary or involuntary dissolution. Why wouldn't government want to simplify / standarize cases of gay couples where one party dies?
I don't agree that gay marriages should allow for child adoption, however.
There is no Constitutional right for men to marry men or for women to marry women just like there is no Constitutional right to abortion.
There is no violation of the Equal Protection Clause because every American is entitled to be married as long as they marry a member of the opposite sex who doesn't happen to be their sister or 4 years old.
This is a tenth amendment issue that should be the province of the states. There is no inalienable right to marriage.
You are free to believe that rights are derived solely from God, but our government is constrained to believe that the rights apply to all living human beings, as that is the law of the land. "Man, considered as a creature, must necessarily be subject to the laws of his Creator, for he is entirely a dependent being....And, consequently, as man depends absolutely upon his Maker for everything, it is necessary that he should in all points conform to his Maker's will...this will of his Maker is called the law of nature. These laws laid down by God are the eternal immutable laws of good and evil...This law of nature dictated by God himself, is of course superior in obligation to any other. It is binding over all the globe, in all countries, and at all times: no human laws are of any validity if contrary to this... Sir William Blackstone
Blackstone was the recognized authority on the law in America for well over 100 years after our founding.
The Founders knew that Rights Came from God. It is the immoral hippies of the 1960's that warped and revised History.
I will stand with Washington, Henry, Adams, Morris, and Jay instead of some doped out hippie whose only concern is where to get more dope and sex.