A federal employment law shields workers from discrimination based on sexual orientation and gender identity, according to a landmark U.S. Supreme Court ruling on June 15.

See full article from SHRM:

In the most anticipated employment decision of the year, the high court found that an employer who fires an individual merely for being gay or transgender violates Title VII of the Civil Rights Act of 1964.

https://www.shrm.org/ResourcesAndTools/legal-and-compliance/employment-law/Pages/Supreme-Court-Title-VII-scope-of-protection.aspx