Id say, as a teacher, it is not my choice as to what a student identifies as, as long as it doesnt break the law, school code, or disrupt the classroom. I doubt very seriously if Biology is being taught ANY different - unless science makes breakthroughs - and then it would be taught like any other new information we have learned.
If this subject was taught specifically, in any way, it would be in a Psychology class, Sociology class, or a class on Government.
And even then, if it was brought up to be specifically discussed in class, it would be to cover different perspectives on the issue, not to dictate to the student what is right or wrong.