Maybe. Typically, the IRS determines marital status by looking at state law in the person’s place of domicile – generally where their permanent residence or primary home is located. Therefore, same-sex spouses who reside in and were married in Maryland will likely be considered married for federal tax purposes.
However, complications and uncertainty with filing status arises for those same-sex spouses domiciled in states with a civil union or registered domestic partnership system, those who lived and married in a state with same-sex marriage that later moved to a state that does not, or those domiciled in a state that does not have same-sex marriage that travelled elsewhere to marry. In these later situations, it is unclear whether same-sex couples may treat each other as spouses for federal tax purposes. The IRS is working on guidance to resolve these issues. In light of the above, same-sex spouses should consult with a tax professional before filing their 2013 tax returns or amending prior tax returns.