At One Time This Was Settled

But with conservative religious judges being packed into the courts we might see all the court precedents thrown out.

Debate about transgender rights and those of religious objectors heats up
Spectrum
By Kelsey Dallas, Deseret News
November 25, 2018

The "T" in LGBT rights will be in the spotlight in 2019, as states and courts across the country debate transgender rights and their impact on the religious groups.
[…]
LGBT rights advocates and religious-freedom activists say they don't want to repeat battles waged over protections for gays and lesbians, which are still ongoing. But the two groups remain divided on the value of religious exemptions to civil-rights law and many people of faith argue the concept of gender identity isn't compatible with their faith.
[…]
Already, religious business owners and faith-based nonprofits have cited conscience rights to defend against allegations of transgender discrimination. Members of the LGBT community, as well as their supporters, argue that religious freedom doesn't include a right to discriminate.

Reducing conflict between the LGBT community and conservative people of faith and reaching compromises will be difficult, but a growing group of leaders is committed to the task, said Naomi Goldberg, policy and research director for the Movement Advancement Project, an independent think tank that does research and advocacy work on LGBT rights.

The radical “Christians” think they should be exempt from the law.

In 1879 Supreme Court case of Reynolds v. United States allowed the banning of plural marriages even though their religion allowed plural marriages.

In the 1963 case of Sherbert v. Verner, the court said that the government needed to demonstrate both a compelling interest and was substantially burdened by a law. The case was about an unemployed person turning down a job because it required Sunday work

In 1990 the court in the case Employment Division v. Smith…

In a 6-3 decision, the Court then held that, because ingestion of peyote was prohibited under Oregon law, and because that prohibition is constitutional, Oregon did not violate the Free Exercise Clause in denying persons unemployment compensation when their dismissal results from use of the drug. 

Then in the case of United States v. Lee the court was asked if an Amish farmer had to pay Social Security to his employees,

a) While there is a conflict between the Amish faith and the obligations imposed by the social security system, not all burdens on religion are unconstitutional. The state may justify a limitation on religious liberty by showing that it is essential to accomplish an overriding governmental interest. Pp. 455 U. S. 256-258. 

In all of these case the Supreme Court found that there were limits to the First Amendment religious freedom clause. That a neutral religious law that didn’t place an undue burden and that the government had a compelling reason for the law was Constitutional but that all may change with the current crop of justices.