It could have been a silly outcry when someone realized this person was of the male gender.
I am sure the person who was outed can expect this for years to come. Our society still has a long ways to go before everyone readily accepts those who feel different than their body's parts say they are.
This could give this student the opportunity to observe their manner of dress, mannerisms, hairstyle, etc....that gave themselves away. Many times I wonder about a person I see, it's human nature to put people in nice comfortable categories, and I simply wonder if they are a cross dresser, in the wrong gender body, or other if they don't fit the generally accepted stereotypes.
One of my friends from long ago was a cross dresser, he was not gay nor did he want to be feminine, he simply loved the feel of women's clothes against his body. He was absolutely wonderful in bed and was very much "the man".
He made the most beautiful woman you could imagine. Something between the gorgeous girl next door and Barbie. He was amazing when he dressed up. I couldn't tell he was not a perfect woman.
He married a gorgeous woman and they have a really nice family now.
So, again, it's up to the person doing the "different" thing to realize they can be found out at any time. It's hard but they do have a lot to deal with their entire life. I wish this student that was found out didn't have to go through this.
On the other hand, if this student that was found out has been having issues in the past with this person that blurted out their secret and a pattern can be proven they perhaps have a case of harassment. They could have threatened them with telling if they didn't do something for them, this person could have previously done any number of things to this person who was hiding their birth gender.
I feel that in that case there would be a plain, easy to follow, interaction trail between them. IF the other person was malicious in their intent then it's a different scenario. If the simply made an spur of the moment utterance then they are not guilty of any sort of wrong doing. The person who was found out just got caught. They can move forward and see how they are accepted or they can deny the allegation, or they can ask to have their transcript forwarded to a more liberal university where they can blend in more readily.