"From the ordinary public meaning of the statute’s language at the time of the law’s adoption, a straightforward rule emerges: An employer violates Title VII when it intentionally fires an individual employee based in part on sex. It doesn’t matter if other factors besides the plaintiff ’s sex contributed to the decision. And it doesn’t matter if the employer treated women as a group the same when compared to men as a group. If the employer intentionally relies in part on an individual employee’s sex when deciding to discharge the employee—put differently, if changing the employee’s sex would have yielded a different choice by the employer—a statutory violation has occurred. Title VII’s message is “simple but momentous”: An individual employee’s sex is “not relevant to the selection, evaluation, or compensation of employees.” (Price Waterhouse v. Hopkins, 490 U. S. 228, 239 (1989) (plurality opinion)). The statute’s message for our cases is equally simple and momentous: An individual’s homosexuality or transgender status is not relevant to employment decisions. That’s because it is impossible to discriminate against a person for being homosexual or transgender without discriminating against that individual based on sex."