A federal lawsuit alleges that U.S. immigration officials illegally funded religious organizations that denied birth control and abortion services to migrant teens.

The complaint, filed two weeks ago in a California district court by the American Civil Liberties Union, alleges that these groups, which include many Catholic-affiliated shelters and charities, are violating legal requirements to provide “appropriate routine medical care,” including family planning and emergency health care services.

The lawsuit is part of a bigger effort to draw attention to religious conflicts in the U.S. healthcare system. One in six patients in the U.S. is currently cared for in a Catholic hospital, according to the Catholic Health Association. At issue is the fact that all Catholic hospitals must abide by a set of Ethical and Religious Directives, or ERDs. Set by the U.S. Conference of Catholic Bishops (USCCB), these rules prohibit abortions, contraception, sterilizations, and certain prenatal tests.

“What’s striking about the broader issue regarding the kinds of exceptions that these large hospitals and religious providers get is that they’ve really floated under the radar,” Douglas NeJaime, a law professor at UCLA, told BuzzFeed News. “We’ve had these laws on the books for a very long time that allow providers to refuse information, counseling, referrals. But as Catholic healthcare plays a bigger role in the U.S., we will see more challenges.”

In 2014, the US Conference of Catholic Bishops (USCCB) received more than $10 million in federal funding to provide care for the unaccompanied migrant teens at issue in the lawsuit.

Representatives from the U.S. Department of Health and Human Services and the USCCB declined to comment, citing the pending litigation. But in past statements, the USCCB has cited laws stretching back to 1973, “enacted to protect rights of conscientious objection,” to defend denial of birth control and abortion services to patients, despite federal funding.

“The vulnerable population that’s at the heart of this case are unaccompanied immigrant minors — young people who have fled their home countries, often to escape abuse, torture, and violence,” Jennifer Chou, an attorney with the ACLU of Northern California, told BuzzFeed News.

Last year, more than 33,000 migrant teens were referred to the Office of Refugee Resettlement by border patrol officials. Nearly a third of them were girls. Though there are no exact numbers, human rights organizations have estimated that as many as six in 10 female migrants are sexually assaulted or raped while crossing the border.

The ACLU complaint was based on a Freedom Of Information Act request that released thousands of documents which, the group alleges, clearly show that the federal agencies were aware that the groups were denying these young girls reproductive care.

“What we’re paying them to do is to provide care, when what they’re really doing is restricting care,” Chou said.