<<If you reframed the argument as: "there's only so many gay people because they want to fit in and be different and being gay is cool now" then it sounds ridic

<<If you reframed the argument as: "there's only so many gay people because they want to fit in and be different and being gay is cool now" then it sounds ridiculous, which tells you everything you need to know about it's validity. Without assigning value judgement to the transgender as a norm/not a norm/social construct/we, you cannot dismiss parent's argument this way. Parent is not claiming 'gays exist only as function of emulating other's behavior'. Parent is claiming there is a social factor that is influencing a younger person to claim being transgender. It is hard to easily dismiss it, because kids do in fact attempt to emulate authority figures ( parents ) and peers ( friends ).