In response to your statements and questions: 1) labels are important for defining things; 2) people who dismiss labels are prone to muddled thinking; 3) yes, such a person had homosexual tendencies -- we can't know if that person knew it or not; 4) it's a contradiction in terms to suggest anything "immutable" can sometimes change so the question should not be answered as it was asked -- but it was a clever, yet unsuccessful, attempt at epistemology; 5) if it is "one-off" then refer to my item 3 above; 6) males do not have hymens so there is nothing to grow back so I assume you were being facetious; and, 7) I would consider such a person as forever bi just as I would consider a spouse who cheats only once on his or her spouse forever an adulterer. Otherwise, one pollutes the traditional definition of "straight," necessitating a new word for a person who never engages in the sexual activity you describe. Why is such a label threatening to you?