Various states now recognize relationships between people of the same-sex, but due to the Defense of Marriage Act, the federal government does not. In the context of income taxes, this combination of state recognition and federal non-recognition of same-sex relationships produces a significant problem for many same-sex couples and some state taxing authorities. Most states have income tax and, typically, state income tax laws “piggyback” on federal income tax laws. Depending on the state, same-sex couples in legally-recognized relationships must file their state income tax returns as married (either “filing jointly” or “filing separately”), as domestic partners, or as parties to a civil union. Such same-sex couples cannot, however, file the...