(Phoenix, Arizona) The city of Phoenix could soon have a domestic partner registry that would give same-sex couples proof of their relationships.

The move comes a month after Arizona voters agreed to amend the state constitution to ban same-sex marriage, although councilors in favor of the registry said plans for it were well in the works before the November election.

“It boils down to a basic human right, and as we enter this holiday season, the issue is even more pronounced,” said Phoenix Councilman Tom Simplot, one of a handful of openly gay elected local officials, told the Arizona Republic.

Simplot said the registry was conceived about five years ago, when some council members began working with local hospitals to assure same-sex partners of patients were given a say in medical care.

Arizona law has since been amended to provide rights to the domestic partners of the sick, but same-sex partners do not have parental rights over their partner’s children. Additionally, some private companies which provide domestic partner health insurance often seek proof of a relationship.

The Phoenix plan would remedy that, say supporters.

To be eligible, domestic partners would have to appear in person at the city clerk’s office and sign a notarized document stating that they are in a committed relationship, are financially interdependent, and live in the same domicile in the City of Phoenix. The document must also state neither partner already is married, that the partners are not blood relatives and each is over the age of 18.

It would cost $50 to be registered and partners would receive a document attesting they are registered.

Opponents, including state Sen. Linda Gray (R), say the the plan is open to abuse.

Gay said that the document would be easy to forge and that the $50 fee would not cover the costs. “I think it creates more problems than it solves,” Gray told The Republic.

The 2006 U.S. Census Bureau showed 133,600 domestic-partner households in Arizona. More than a quarter of them were in Phoenix.

The City of Tucson has had a similar registry since 2003.