The case of Adoptive Parents v. Baby Girl is also unusual because of the odd lineup: Justice Alito delivered the opinion of the Court, in which Chief Justice Roberts, and Justices Kennedy, Thomas, and Breyer joined. Thomas and Breyer also filed concurring opinions. Justice Scalia filed a dissenting opinion, and so did Justice Sotomayor who was joined by Justices Ginsburg, Kagan, and Scalia in part.
Although this is not as odd as the lineup in the Prop. 8 case, Hollingsworth v. Perry: Chief Justice Roberts delivered the opinion of the Court, in which Justices Scalia, Ginsburg, Breyer, and Kagan joined. Justices Kennedy filed a dissenting opinion, in which Justices Thomas, Alito, and Sotomayor joined.