Houston Mayor Annise Parker on Wednesday announced that the city would extend benefits to the spouses of gay city employees.

“Based on the right to equal protection under the law, it is unconstitutional for the city to continue to deny benefits to the same-sex spouses of our employees who are legally married,” Parker said in a written statement. “This change is not only the legal thing to do, it is the right, just and fair thing to do.”

The city's action is based on a legal opinion from City Attorney David Feldman.

According to The Houston Chronicle, Feldman cited in his opinion the U.S. Supreme Court ruling that gutted the Defense of Marriage Act (DOMA) and led to the federal government recognizing the legal marriages of gay couples.

In 2001, voters approved a city charter amendment that prohibits the city from offering same-sex benefits. However, the city said that the amendment specifically permits benefits to be provided to the “legal spouses” of employees.

“After a careful review of recent case law, the city legal department believes continued application of the charter amendment so as to deny same-sex spousal benefits would be unlawful because it treats employees differently on the basis of sexual orientation,” the city said.

Parker, an out lesbian recently elected to a third term, said: “I can only assume that it was contemplated that there would never be a time when same-sex couples were in legally sanctioned relationships.”

At least five other large Texas cities – Austin, Dallas, El Paso, Fort Worth and San Antonio – have extended benefits to gay couples through domestic partnerships. Houston is the first to limit such benefits to married gay couples.

An upcoming New Mexico Supreme Court decision is expected to legalize marriage in the state, shortening the distance Texas gay couples need to travel to obtain a marriage license.

(Related: New Mexico Supreme Court likely to legalize gay marriage, both sides say.)