Roughly two dozen current and former Republican lawmakers filed a friend-of-the-court brief urging the New Mexico Supreme Court to declare that state law prohibits gay marriage.

The GOP lawmakers are represented by the Christian conservative group Alliance Defending Freedom (ADF).

The high court has agreed to hear a case related to whether New Mexico's marriage laws, which are phrased in a gender-neutral manner, prohibit gay couples from marriage.

The debate turned into action on August 21, when Dona Ana County Clerk Lynn Ellins decided the question independently and started issuing marriage licenses to gay couples. Since then, seven additional counties, representing nearly 60 percent of the state's population, have joined Dona Ana in issuing such licenses. Some of the counties were ordered to act by a district judge.

Last month, Judge Alan Malott of the Second Judicial District Court issued a judgment against the county clerks of Bernalillo and Santa Fe counties and the state of New Mexico declaring that, to the extent New Mexico law prevents gay and lesbian couples from marrying, “those prohibitions are unconstitutional and unenforceable.”

The lawmakers argued in their filing that gay couples are not similarly situated to heterosexual couples “when viewed in light of the government's overriding purpose for marriage” and therefore not allowing gay couples to marry does not violate New Mexico's Equal Protection Clause.

The “obvious” difference, the lawmakers wrote, is biological.

“The precise classification at issue here is based on an obvious biological difference between same-sex couples and opposite-sex couples: that sexual relationships between opposite-sex couples have the natural capacity to create children, but sexual relationships between same-sex couples do not.”

The lawmakers also argue that the court's protection is not needed because gays possess tremendous political power.

“[I]individuals who identify as gay – even though they comprise less than 4% of the population [...] – have achieved a disproportionate level of political power and success, particularly on the issue of marriage,” the 49-page brief states.

The high court is scheduled to hear oral arrangements in the case on October 23.