Those reading the newspapers know that the Supreme Court recently ruled in Bostock v. Clayton County that employment discrimination based on sexual orientation or gender status is discrimination based on sex. Why is this so? As I have argued for many years, an employer can’t act on the basis of sexual orientation or gender status without first making judgments about sex. Or as the Court put it, “An employer who fires an individual for being homosexual or transgender fires that person for traits or actions it would not have questioned in members of a different sex. Sex plays a necessary and undisguisable role in the decision, exactly what Title VII forbids.” The Court also discussed causation at length. It emphatically rejected the notion that but-for causation means sole cause, primary cause, dominant cause or anything of the sort. All that is required is that the prohibited criterion made a difference.