Original sentence: Although it seems clear that LGBT people have existed in every culture throughout human history, much of written history omits their place in their societies.This continues today, though in fewer areas than would have been seen in the past.Today, many societies continue to disparage non-heteronormative values and mores.Until the late 20th Century, it was widely believed in the Western world that non-mainstream forms of sexuality and gender-identity were mental illnesses
Edited sentence: Although LGBT people have existed in every culture their existence in written history has largely been erased and still today many societies disparage non-heteronormative values and mores.Until the 20th Century, it was widely believed in the Western world that non-mainstream forms of sexuality and gender-identity were mental illnesses