Today, same-sex marriages are legal in the US. This made uniform the tax and planning aspects for all married couples, whether same- or opposite-sex. It also brought about fairness in certain tax benefits that were previously only available for opposite-sex couples.
Registered Domestic Partnership
In contrast, Registered Domestic Partners are not considered spouses under federal law. Therefore, it's important to remember that many of the federal tax benefits afforded to married, same-sex couples are not available to Registered Domestic Partners.
In California, however, Registered Domestic Partners have the same rights and responsibilities as married couples, resulting in some very unique estate planning issues for couples who choose to be in Registered Domestic Partnerships.
The ease with which individuals may enter into Registered Domestic Partnerships can causes issues when they seek to later marry someone else.
Registered Domestic Partners who separate without taking any of the proper legal steps to dissolve the registered domestic partnership are not legally able to marry someone else. As a result, people who believe they are validly married to their new partner, may not actually be in a legal marriage because they failed to have a prior registered domestic partnership dissolved.