PHOENIX - Saying the interests of Attorney General Tom Horne may not align with theirs, Maricopa County Attorney Bill Montgomery and a religious-based law firm want federal court permission to defend a state law banning abortions based on the gender or race of a child.

In legal filings Monday, the lawyers told a federal judge they have a perspective about why the 2-year-old law is legal that Horne may not share. They contend the interests of Montgomery and state Rep. Steve Montenegro, R-Litchfield Park "might not be adequately represented" if Horne defends the case.

Horne said he has not decided whether he will allow others to take the lead in defending the law. But he has been reticent to be at the forefront in defending other recent legally questionable changes in abortion laws that have wound up in court.

He let Montgomery defend a ban on abortion at 20 weeks, a move struck down by the 9th Circuit Court of Appeals. And the Alliance Defending Freedom, a privately financed anti-abortion group, is defending a law allowing Arizona to cut Medicaid family-planning funds to Planned Parenthood because the organization also offers privately funded abortions. A trial judge has upheld the law.

The 2011 law makes it a felony, punishable by up to seven years in prison, for a doctor to perform an abortion "knowing that the abortion is sought based on the sex or race of the child or the race of the parent of that child." Challengers, including the NAACP and the National Asian Pacific Women's Forum, contend the law, believed to be unique in the country, is an unconstitutional infringement on the right of minority women to terminate their pregnancy without being questioned about the reason why.

Montgomery and attorney Casey Mattox of the ADF say the law is "race and gender neutral" and does not violate constitutional equal protection provisions. They also said lawmakers "have the right and the duty to enact laws that protect all citizens, born and unborn, from invidious discrimination based on race or gender."

But to make that case in court, they must convince a judge they should be allowed to defend the law.

Montgomery said allowing him to intervene in the case for Maricopa County residents will allow him to "protect and preserve a statute passed for their protection." He said as the person who would be prosecuting doctors who violate the law, his approach to defending the law "is sometimes different" than Horne's, who does not have that role.

Mattox said Horne might simply try to defend the law as a permissible state regulation of abortion.

But Mattox said there are broader issues, including the motives of Montenegro in sponsoring the measure and why the Frederick Douglass Foundation, an anti-abortion group he also represents, supports the law.

"The plaintiffs have made virtually their entire case that the motivations for this law were somehow less than honorable," Mattox said, which is of "great concern" to Montenegro and the Frederick Douglass Foundation whose members "find themselves being told that a law that they advocated for because it would protect African-Americans from discrimination is somehow motivated by discriminatory ideas."

Critic Monica Ennis, past president of the Arizona Black Nurses Association and member of the NAACP, called the law "an insult to the intelligence of African-American and Asian women."

The lawsuit also says the purpose of the law is to reduce the rate or number of black and Asian women who have abortions, "but not women of any other race." And it charges the law is "based on racist and discriminatory stereotypes" about both groups.

Montenegro, the bill's sponsor in 2011, argued it was needed because there was evidence blacks have a higher abortion rate than other races. And he said those who perform such procedures are "the people behind genocide."

He also cited evidence, much of it from Asian countries, that women there were far more likely to abort a female child than a male. That got extrapolated to questions about the practices of Asian women in Arizona, even though there was no evidence presented linking abortions here to gender selection.

In the legal papers filed Monday, Montgomery and Mattox contend some of the statements attributed to Montenegro and other supporters were "incomplete, out-of-context and misrepresented" what actually occurred.