While there is no answer yet on this issue, our country is getting closer to an answer. While marriage is a power delegated to the states, the federal law DOMA has stated that states need not give Full Faith and Credit to a legal same sex marriage from another state.
On February 7, 2012 a California Federal Appeals Court struck down California's ban on gay marriages. However, the Court did not address whether other states or the federal government were required to recognize same-sex marriage. Accordingly, the decision will likely be appealed and reach the United States Supreme Court in the upcoming year.
The decision rendered Tuesday by the 9th Circuit was purposely narrow in scope so as to not be the subject of scrutiny upon appeal to the Supreme Court. While the Court determined that proposition 8 violated the 14th Amendment, Equal Protection clause, the Court did not state whether there is a fundamental right to marry someone of the same-sex.
Thus, we are closer to learning the future of DOMA and same-sex marriage in our country.