Non-heterosexual is a sexual orientation or sexual identity that is not heterosexual. Many gay, lesbian and bisexual people were born into cultures and religions that stigmatized, repressed or negatively judged any sexuality that differed from a heterosexual identity and orientation.
Non-heterosexual is found predominantly in research and scholarly environments possibly as a means to avoid terms deemed politically incorrect like Que es una persona heterosexual discriminationdykegaybisexualetc. In a book that integrates "the academic disciplines of cinema studies, sociology, cultural and critical studies" regarding the Big Brother phenomena, non-heterosexual was used as a universal term to help compare information from over thirty countries.
Non-heterosexual is also used when studying lesbian and gay families and family structures. Non-heterosexual is also rather problematically used as a catch-all term, encompassing gender identity as well as sexual identity.
Heterosexuality as a categorization and as a term, was not created until the late nineteenth century, prior to this relations between the sexes were not believed to be overtly sexual. The term heterosexuality was created as a way to subjugate and other anyone who did not confirm to mainstream ideals of sexuality. It was a term that created a sense of validation that heterosexuality was the normal, healthy version of human sexuality.
This is seen as problematic as sexual orientation and gender identity are different. However the distinction between the two is relatively modern. While trans people and people with non-binary gender identities are part the LGBTQ community, having been subjected to many of the same injustices,  labelling trans and genderqueer identities under the term non-heterosexual blurs the important differences between sexual orientation and gender identity.
Because it is so non-specific it is open to interpretation by those outside the LGBTQ community or by those who are not as educated about the spectrum of sexual orientations and gender identities leading to a greater emphasis on the identities that are already well known and an erasure of the identities that are already not a large part of mainstream dialogues.
From Wikipedia, the free encyclopedia. The Spectre of Promiscuity: Retrieved 24 July Queer Man on Campus: New Directions For Women's Studies. Journal of College Student Development. Archived from the original on 14 October Controversies in Feminist Social Ethics. Continuum International Publishing Group.