A conservative Christian organization has sued the city of Austin in federal court in hopes of overturning a nondiscrimination ordinance that offers employment protection based on sexual orientation and gender identity.

The Houston-based U.S. Pastor Council argued that the ordinance is unconstitutional and invalid because it does not include a religious exemption for 25 member churches in Austin that refuse to hire gay or transgender people as employees or clergy.

“These member churches rely on the Bible rather than modern-day cultural fads for religious and moral guidance,” said the lawsuit, filed over the weekend in Austin federal court. “They will not consider practicing homosexuals or transgendered people for any type of church employment (or position in the clergy)."

Unless an exemption is included to honor the sincere religious beliefs of such churches, Austin should be blocked from enforcing its employment nondiscrimination ordinance for violating the free exercise of religion by subjecting member churches to fines and other penalties, the lawsuit argued.

“Any law that purports to regulate church hiring decisions inflicts injury in fact by restricting the church’s autonomy,” the lawsuit said.

The lawsuit also seeks a court order declaring that churches affiliated with the U.S. Pastor Council have a right under the U.S. and Texas constitutions to exclude the hiring of gay and transgender people and, if required by church bylaws, bar women from serving in senior pastor positions.

Austin Mayor Steve Adler, who was named in the lawsuit with Austin Human Rights Commission Chairwoman Sareta Davis, said the hiring ordinance will be vigorously defended.

"Nondiscrimination is a core value in Austin," he said. "This is a city where we want everyone to have equal opportunity and respect and to feel safe."

Austin spokesman David Green said: “The city is proud of our anti-discrimination ordinance and the protections it provides. The ordinance reflects our values and culture respecting the dignity and rights of every individual."

Austin City Code prohibits employers from hiring decisions that discriminate based on “race, color, religion, sex, sexual orientation, gender identity, national origin, age or disability.”

The ordinance allows two types of organizations, faith-based schools and organizations, to limit hiring to members of a particular religion, but the pastors’ lawsuit argued that the exemptions do not go far enough.

“Neither of these two exemptions accommodates churches that refuse to hire women, practicing homosexuals or transgendered people as clergy,” the lawsuit said. “There are no exceptions to the ban on sex discrimination, and there are no exceptions to the ban on discrimination based on sexual orientation or gender identity.”

In addition to alleging constitutional violations, the lawsuit argued that Austin’s hiring ordinance violates the Texas Religious Freedom Restoration Act, which says governments cannot “substantially burden a person’s free exercise of religion” except to further a compelling public interest.

Dan Quinn, spokesman of the Texas Freedom Network, which has opposed previous efforts by the Pastor Council to limit gay rights, said the lawsuit was an unnecessary and mean-spirited attempt to obtain a court-granted license to discriminate.

"I know of no instance in which a church or religious association has been forced to hire a gay person in violation of their religious beliefs," Quinn said, adding that church hiring practices already are protected by the Constitution.

"This lawsuit isn’t about protecting religious freedom. This is about sweeping away anti-discrimination protections that have been on the books for decades," he said.

Dave Welch, head of the Pastor Council, referred inquiries to the group's lawyer, Jonathan Mitchell, who did not return a phone call Tuesday.

During the 2017 legislative sessions, Welch and his organization took a leading role in promoting bills to ban transgender-friendly bathroom policies in public schools and government buildings. Those bills were blocked by moderate Republicans in the Texas House, but supporters have indicated that they will try again when the Legislature convenes in January.

The Pastor Council also supports laws allowing government workers, judges and private businesses to opt out of serving same-sex couples seeking a marriage license or marriage-related services — bills that also didn't gain traction in previous legislative sessions.

Mitchell, the Pastor Council's lawyer, previously served as the solicitor general of Texas, the chief appellate lawyer in the attorney general’s office. Last year, President Donald Trump nominated Mitchell as chairman of the Administrative Conference of the United States, a federal agency that seeks to improve government procedures. The U.S. Senate has not yet voted on his confirmation.