lcgomez

This is a very simple analysis. There are only two distinct biological genders. As with the rest of our biology, some mutations are bound to occur in nature by virtue of biology itself. These mutations do not represent new genders (or a new species with 6 fingers in one foot, for that matter) but are strictly mutations.

There are, on the other hand, many and varied SEXUAL PREFERENCES in humans. The most prevalent being heterosexuality, second would be homosexuality and so on. We might have novel sexual preferences appearing and others disappearing by virtue of society, learning and environment, as well as biological or personality causes. These must no be confused as genders, but regarded and respected as preferences.
These preferences might be ample, surpassing chosen sexual behaviors, and including identity and "look and feel" behaviors. All of these are, by the way, learned.

Gender existed first as a gramatical differentiation meaning "kind" or "type". And sex was a form of "type" or "kind" in species with sexual reproduction (as opposed to asexual reproduction) and the word gender was used to mean sex, in the reproductive way.

Consequently, gender was indeed, binary for humans in the original meaning of the word "gender".

The word gender has evolved to include different definitions, one of which is described by @freyaehope, a social construct.

If we take the word gender to have this new meaning (similar to the personality meaning), then of course, there are many genders.

The argument should not be semantic, I agree. Most people that "do not accept many genders" are not accepting the semantic meaning equalizing gender with sex (reproductive, biological sex).

If we used another word, I think the argument would arise more freely and be accepted widely. I used sexual preference, for example. But any word could help us close the bridge. The importance of the word should not be above the importance of the concept?

If the original questions was worded: Are there different sexual preferences? or even more ample: Are there many different personalities and ways of thinking and acting in societies, sexually and otherwise?

I think 100% will agree there are.