Michigan is illegally allowing faith-based organizations to reject same-sex couples who want to adopt children or become foster parents, the American Civil Liberties Union (ACLU) said Wednesday in a lawsuit challenging the practice.

The state pays groups such as Catholic Charities and Bethany Christian Services to place children from troubled families with new families. The ACLU said Michigan is violating the U.S. Constitution by allowing the groups to use a religious test to carry out public services.

Allowing agencies to discriminate could be the difference "between a child finding a permanent loving home or staying in the system," ACLU attorney Jay Kaplan said.

Republican Gov. Rick Snyder signed a law in 2015 that says child-placement agencies aren't required to provide services that conflict with their beliefs. It was signed, however, before the U.S. Supreme Court legalized gay marriage.

The Department of Health and Human Services declined to comment on the lawsuit, which was filed in Detroit federal court, and instead referred to the law.

The plaintiffs in the ACLU lawsuit include Dana and Kristy Dumont, who said they were turned down by two faith-based agencies in the Lansing area. Read more via NBC