The word deviant doesn’t really mean anything, as far as science is concerned.

So no objectively Gay people are not deviance since morality is a human construct(or if so that is a philosophical question).

The best way I could rewrite this question is

A. Are we evolutionarily predisposed to find people with alternative* sexual preferences distasteful or unpleasant.?

B. Are alternative* sexual preferences evolutionarily harmful to society?

C. Are alternative* sexual preferences harmful to one’s own evolutionary path?

D. If the above statements are true, will the psychological and societal be so detrimental on the individual so much that it is necessarily better to engage in alternative* sexual desires?

*alternative in this context meaning anything outside of a heterosexual relationship, however the questions can be narrowed down to what ever sexual preferences you are inquiring about.

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I will not offer my own opinion about this, nor will I even present any actual science but I will say this, I don’t think it is as black and white as you might assume.