Other questions that you have asked lead me to assume that you are asking about gay marriage in the United States. I will base my answer on that assumption.
At the moment, gay marriage is largely a matter for the individual states to decide. Each state has the right at this point to decide whether it will allow gay marriage. As of right now, 13 states and the District of Columbia allow gay marriages. The other states have a variety of laws regarding gay marriages and domestic partnerships.
An important fact to note is that states that do not allow gay marriages do not have to recognize such marriages that have been solemnized in states that do allow them. This means that a gay couple that gets married in Washington, for example, would not be legally married in the eyes of state law if they moved to Texas.
At the federal level, one part of the Defense of Marriage Act was declared unconstitutional in the summer of 2013. This means that the federal government must now recognize the validity of gay marriages performed in states that approve such unions.
Thus, there is no blanket right to gay marriage in the US, but 13 states do grant that right and the federal government is now obligated to recognize gay marriages from those states.
I'll assume you're talking about gay marriage in Australia.
Gay marriage is described as a homosexual couple (i.e a man and a man, or a woman and a woman) being legally bonded together under the title of marriage. In Australia, gay marriage is currently not recognised, however there are movements being done in order to change this.
Gay marriage cannot be implemented until federal parliament (that is, the House of Representatives and the Senate) passes a bill dictating that gay marriage can now be legally recognised. Currently, a conservative party called the Liberal National coalition has the majority in the House of Representatives. Tony Abbott, the leader of the party, has said he is not in favour of gay marriage, meaning the bill is unlikely to be made while the coalition is in power. The opposition parties, the Australian Labor Party, a centre left party, and the Australian Green Party, a left wing green politics party, have both said they are in favour of gay marriage.
So, in Australia, we are unlikely to see a bill for gay marriage being introduced for at least another three years. Labor and the Greens are in favour, but the Coalition are not. The public are currently reported to be in favour of gay marriage, but generally speaking, most conservative political parties are for traditional, heterosexual marriage.