What does it mean to discriminate "because of sexual orientation?" This legal question will arise increasingly as many states and municipalities enact laws that prohibit discrimination because of sexual orientation. Without evidence of animus, plaintiffs will likely resort to evidence of sexual orientation stereotyping. How should courts determine whether evidence is of sexual orientation stereotyping, and therefore evidence of sexual orientation discrimination? This question is important for courts and litigants who will increasingly face the question, as well as for those invested in anti-essentialist antidiscrimination law more broadly. When the law attempts to define identity categories by offering universalizing definitions, it ultimately excludes those who exist on the margins, and it tends to reinforce regressive and narrow views of what that identity category means. Thus, how courts approach stereotyping evidence determines both the contours of the protected trait and who is protected from discrimination. This Article illustrates the dynamic nature of sexual orientation as a protected trait by discussing how expectations and expressions of gay identity diverge within the gay community. It focuses on divisions along several axes: masculine gay men who discriminate against effeminate gay men; discrimination stemming from respectability politics and how gay people organize and structure their romantic and sexual lives; and discrimination against gay people on the basis of class, race, and geography. We all express sexual orientation differently, and the law must protect individuals who are discriminated against because they are gay in the way that is best for them.