Two lesbian couples on Wednesday filed a lawsuit challenging New Mexico's refusal to issue them marriage licenses.

The plaintiffs, Kim Kiel, 44, and Rose Griego, 47, and Miriam Rand, 63, and Ona Lara Porter, 66, applied for and were denied marriage licenses by the Bernalillo County Clerk.

The couples are being represented by the American Civil Liberties Union (ACLU), the ACLU of New Mexico, and the National Center for Lesbian Rights (NCLR).

According to an NCLR release, New Mexico is the only state in the nation that does not either explicitly recognize gay couples through marriage or civil unions or ban recognition of such unions by statute or constitutional amendment.

“Marriage matters,” said Griego in a statement. “Kim and I have already made a lifelong commitment to one another, but marriage says 'family' in a way that no other word can. It's important to us that the State of New Mexico – our home, the place where we live, work and raised our family – recognizes and respects our relationship.”

Kiel and Griego have been together for 8 years and live in Santa Fe, while Rand and Porter have been together for 25 years and live in Albuquerque. Rand and Porter raised three children and continue to care for their middle daughter, who has multiple sclerosis, and their granddaughter, who has cerebral palsy.

The suit comes two days after Santa Fe Mayor David Coss and City Councilor Patti Bushee announced they are backing a city resolution declaring that nothing in state law prohibits gay couples from marrying. The resolution, expected to be introduced Wednesday, is based partly on an opinion issued by City Attorney Geno Zamora.

Zamora's legal memo says, “New Mexico's statutory definition of marriage is gender-neutral. Since New Mexico does not define marriage as between a man and a woman, and since New Mexico does not prohibit same-sex marriage, same-sex marriage is permitted in New Mexico.”

(Related: Gay marriage legal in New Mexico, Santa Fe Mayor David Coss Argues.)