This really happened.

A 20-something woman was at a party, and claimed afterwards that she had been raped.

The man she identified was prosecuted for this. The jury were told one apparently relevant fact about her; one apparently relevant fact was withheld from them on the instructions of the male judge.

The man was acquitted. When told the fact that had been withheld, the faces of the members of the jury indicated that they suddenly realised that they had made a mistake.

What were the two facts?