'Gender non-conforming behavior'? This is a socio-cultural category, not (as commonly believed) a natural one.  Boys and girls tend to behave in culturally conditioned ways rather than genetically pre-determined ones. Problems associated with these often-rigid categories (like bullying of those who don't conform) are learned behaviours, just  as the categories themselves are learned concepts.  

This applies also to same-sex attraction. Traditional categories of sexual attraction are socio-cultural (learned) rather than natural; typically however, they are viewed by the hetero-normative majority as natural. Hence the historical (and almost universal) intolerance, both moral and social, of LGBT people.

Until same-sex attraction is universally  accepted as an entirely natural category of human activity (along with so-called 'gender non-conforming behavior'), the intolerance and bullying of innocent people will continue.