Sexual Preferences are personal and optional. Biology is not.
I have no problems with any individual's sexual behavior or preference, within the law. Clothing, mannerisms and other such displays are all fine with me.
However, as a free thinking rational person, I should not be forced to pretend that a boy is a girl. One's actual gender is determined before birth, at the moment of conception. And it remains this way until our very last breath on earth. Some children near puberty switch back and forth with great sexual confusion. However, no amount of surgery or behavior modification can ever change our gender because it is locked into every cell of our body, with a pair of exactly the same DNA chromosomes that we were born with.
So let people express themselves however they wish, but do not force my daughter to share restrooms/showers with your son. There must be a recognition that there are immutable biological differences that drive some policies, and privacy, and medical care, which cannot be trumped by a teenager's sexual preference.