In Massachusetts v. United States Department of Health and Human Services (2012), Lynch joined a unanimous panel in holding (in an opinion written by Judge Michael Boudin) that the Defense of Marriage Act (DOMA) was an unconstitutional violation of the equal protection principles of the Fifth Amendment, because it denied to same-sex couples the federal benefits enjoyed by opposite-sex couples.Recent Case: Equal Protection — Sexual Orientation - First Circuit Invalidates Statute that Defines Marriage as Legal Union Between One Man and One Woman. — Massachusetts v. United States Department of Health & Human Services, 682 F.3d 1 (1st Cir. 2012), 126 Harv. L. Rev. 611 (2012).
