What is the test for a unanimous verdict in a sexual assault case?

"Like the 'reasonable doubt' standard, which was found to be an indispensable element in all criminal trials in In re Winship, 1970, 397 U.S. 358 [90 S.Ct. 1068, 25 L.Ed.2d 368] ..., the unanimous jury requirement 'impresses on the trier of fact the necessity of reaching a subjective state of certitude on the facts in issue'. 397 U.S. at 364 [90 S.Ct. at 1072].... The unanimity rule thus requires jurors to be in substantial agreement as to just what a defendant did as a step preliminary to determining whether the defendant is guilty of the crime charged. Requiring the vote of twelve jurors to convict a defendant does little to insure that his right to a unanimous verdict is protected unless this prerequisite of jury consensus as to the defendant's course of action is also required." (United States v. Gipson (5th Cir.1977) 553 F.2d 453, 457-458 fns. omitted.)