Societies and cultures regulate themselves by adopting norms - rules embedded in religion, tradition, law and superstition. Western culture, by which I mean most of the human race, is in the process of adopting and sometimes furiously resisting tectonic scale changes in our social norms, especially those relating to gender roles. Most of this struggle involves political and economic power, but a not entirely minor sidelight involves the definition of appropriate sexual behaviors. Many practices which were severely criminalized everywhere are now officially sanctioned or even protected by law in many places while still being punishable by death in others.
I don't think that one can doubt that both the racial civil rights and homosexual rights movements grew organically out of feminism and the struggle for the female franchise. That it turn grew out of the earlier democratization of the vote. At one point it was quite acceptable in polite company to complain that giving the women the vote was unnatural. Being homosexual or transgender is certainly not "unnatural" but it is unusual, and that was a good enough excuse for many societies to punish them furiously.
Not every change is toward more tolerance. Some once standard behaviors are now forbidden. An Idaho man was sent to jail for taking his 14 old daughter across State lines to marry the man who got her pregnant.