Alito, J., dissenting
conduct is not sex discrimination, the statute does not apply. Thus, this lesson simply takes us back to the question whether discrimination because of sexual orientation or gender identity is a form of discrimination because of biological sex. For reasons already discussed, see Part I–A, supra, it is not.
It likewise proves nothing of relevance here to note that an employer cannot escape liability by showing that discrimination on a prohibited ground was not its sole motivation. So long as a prohibited ground was a motivating factor, the existence of other motivating factors does not defeat liability.
The Court makes much of the argument that “[i]n Phillips, the employer could have accurately spoken of its policy as one based on ‘motherhood.’” Ante, at 14; see also ante, at 16. But motherhood, by definition, is a condition that can be experienced only by women, so a policy that distinguishes between motherhood and parenthood is necessarily a policy that draws a sex-based distinction. There was sex discrimination in Phillips, because women with children were treated disadvantageously compared to men with children.
Lesson number two—“the plaintiff’s sex need not be the sole or primary cause of the employer’s adverse action,” ante, at 14—is similarly unhelpful. The standard of causation in these cases is whether sex is necessarily a “motivating factor” when an employer discriminates on the basis of sexual orientation or gender identity. 42 U. S. C. §2000e–2(m). But the essential question—whether discrimination because of sexual orientation or gender identity constitutes sex discrimination—would be the same no matter what causation standard applied. The Court’s extensive discussion of causation standards is so much smoke.
Lesson number three—“an employer cannot escape liability by demonstrating that it treats males and females comparably as groups,” ante, at 15, is also irrelevant. There
