Redefinition of marriage is not a human right, sorry. I can't decide I'd like to marry my work and have society accept that as marriage. Marriage has a definition, that up until now hasn't included gay couples. Changing that is not trivial, is not a law of nature and is not supportable on human rights grounds.
Let's, for the sake of argument, assume that gay couples are already free to live together and enjoy the protection given to married couples: inheritance, hospital/prison visiting rights, IRS deductions, [whatever social right I may be missing]. I know that is not the case; bear with me.
Now, imagine that a group wants to reserve the right to call marriage limited to a long term commitment between man and woman. Also imagine that gay couples want to call their long term commitment a marriage.
Now, you have an unsolvable problem. Both groups may argue that it is their right to define what marriage is all the way to the end of times. The problem is mostly with the naming of the concept; it is not with rights attributed to gay couples. Framing the discussion around the concept is actually hurting LGBTQ movements.
My personal opinion? Grant all, and I mean all rights to gay couples that classic couples have. Use the first-come-first-served rule and maintain the term marriage to mean a classic family. Create a new term for gay couples.
Give it two generations and this whole shout war will subside, and by then everyone will naturally call gay couples married couples, just like any other. In the mean time, important goals can be reached faster (like visiting rights).