Most people, gay or not, should consider making an estate plan.
However, same-sex couples have more to gain from making an estate plan than do straight couples, because in many states, they cannot marry, making them ineligible for the benefits of laws designed to protect married people and their assets. [NOTE: Since marriage equality was affirmed by the Supreme Court, this is no longer accurate. However, much of this article and its link continue to apply.) An estate plan can also help clarify the nature of their relationship for those family members or professionals who may not understand it or approve of it.
State and federal laws affect how couples own property together, who gets which assets when one member of a couple dies, how taxes are calculated and paid, and who has the right to make health care decisions if one member of the couple becomes incapacitated. Generally, laws protect spouses in all these situations. For examples, spouses have a right to visit each other in the hospital, and to inherit from one another. They get tax breaks as well. But because same-sex couples cannot marry in most states, they are denied these benefits. They need to create estate planning documents that spell out their wishes and, as far as possible, make them legally binding.
To learn which specific estate planning tools same-sex couples should consider, read 6 Key Estate Planning Issues for Gay Couples.