Genitalia-based categorizations:
1: People who have penises are male, and people who have vaginas are female.
1.1: Intersex people are ignored.
1.2: Intersex people are not ignored.
1.2.n: (coming soon?)
Chromosome-based categorizations:
1: People with XX chromosomes are females, people with XY chromosomes are male.
Reproduction/fertility-based categorizations:
1: People who can impregnate females are males, people who can be impregnated by males are females, and people who can neither impregnate nor be impregnated (e.g. pre-pubescent children, sterile people, old "women") are genderless.
1.1: "Genderless" is synonym with "non-binary" and is considered a gender on its own.
1.2: "Genderless" is considered as a lack of gender. This is similar to the debate of whether or not atheism is a religion, or a lack of religion (ignoring the whole discourse regarding the idea that monotheism/polytheism/pantheism/etc. are also not religions, or that some forms of Buddhism and Satanism are atheistic, but this would be off-topic to list here).
Self-identification based categorizations:
1: People who self-identify as male are males, people who self-identify as females are females. There are only two genders, "non-binary" is not a thing.
2: Same as #1 but non-binary is a thing, so there are three possible genders.
3: Same as the above but gender is a spectrum rather than having a definite number.
Mixed categorizations:
1: People who have penises are male, people who have vaginas are female, intersex people are considered non-binary, but people even if male or female can self-identify as non-binary (but not as the opposite gender), making this view a syncretism between genitalia-based and self-identification. Does not fit the current paradigms of how people think in society, but it's thinkable, so... in this page it goes ;)
2: People who have penises AND do not cry are male. People who have penises and cry are female, as well as intersex people and people who have vaginas.
3: People who have penises AND do not cry are male. People who have vaginas AND do not fart (or at least, fart only secretly, without anyone else knowing, and not admitting it) are female. People who have penises and cry, as well as people who have vaginas and fart, are considered either non-binary, or the opposite gender.
3.1: It's still possible for people who are considered "male" and "female" within this categorization to identify as non-binary if they wish.
3.1.1: They can identify as non-binary but not as the opposite gender.
3.1.2: They can identify as the opposite gender but not as non-binary.
3.1.3: They can identify as either the opposite gender or as non-binary.
3.1.4: They cannot identify as the opposite gender nor as non-binary.
4: People with penises are male but they can identify as females if they want. People with vaginas are females but cannot identify as male.
5: (Vice-versa of the above). People with penises are male and cannot identify as females. People with vaginas are females and can identify as male if they wish.
5.1: Non-binary does not exist in this categorization.
5.2: Non-binary exists in this categorization.
5.2.1: Only people with penises can identify as non-binary.
5.2.2: Only people with vaginas can identify as non-binary.
5.2.3: Both people with penises and vaginas can identify as non-binary.
5.2.4: Only billionaires can identify as non-binary.
5.2.4.1: Billionaires are necessarily non-binary, regardless of their own self-identification or genitalia.
5.2.5: People can only identify as non-binary during Full Moon.
5.2.6: People are necessarily non-binary during Full Moon.
5.2.7: People are necessarily non-binary during Full Moon, but only if they eat tomatoes.
n: alright, alright, I get it. I can create any silly ad-hoc conditions that are either necessary or sufficient to be classified as one gender (or lack thereof). The idea that gender is defined by genitals (or self-identification, or anything else really) is as arbitrary as anything else, but this likely has to do with linguistics and definitions of the words rather than some ontological thing going on (and even this is up to debate, like literally anything else here in this philosophy section... likely there may be a distinction between linguistic prescriptivism vs linguistic descriptivism). The pattern is clear by now. I really need better ways to generalize, like "gender (and anything else, any other word/concept/etc.) can be formulated with any ad-hoc conditions and definitions, it's "society" who decides what words mean and how things are categorized and grouped together (linguistic descriptivism), here are some examples of how a hypothetical society (which may not be English-speaking and may have words for gender that are not directly translatable into English) may conceptualize gender:", or "no, words have an objective meaning and are not decided by society, and society can be objectively wrong (linguistic prescriptivism), here are what gender objectively means:". Redefinition of words while maintaing their original connotation may happen in human societies for various reasons, but this would require a separate page. Of course there can be discussions that are not linguistic in nature but more ontological ("how things actually are"). Yet another type of discussion (perhaps the most common on social media?) is that of moral consequentialism i.e. "what happens (e.g. to society or individuals or groups of people e.g. "biological women") if people believe in these things/use these words/concepts in this way (rather than in this different way)?". Anyway, let's move on:
Monolithic vs modular conceptions of gender:
Monolithic: a person is either male, female, non-binary (if allowed), somewhere within the spectrum (if allowed), something else (if allowed), multiple genders simultaneously (if allowed), but there is no distinction between various "aspects" of one's own gender.
Modular: a person's gender can be divided in various "aspects" - which are called "modules" - and each module has a different gender assigned to it. For instance, one can be male in the "genital" module (i.e. that person has a penis), and female in the "appearance", "behavior" (if one believes that behavior differs from males and females, either for cultural reasons, biological reasons, or both) and "conformity to gender roles" modules. The modular conception of gender can be further divided into "solvable modular" and "unsolvable modular". Solvable modular maintains that, while each module may have a different gender, it is possible to say that a person as a whole belongs to one (or more than one, if allowed) gender. Solvable modular can be further divided into emergentist solvable modular and reductionist solvable modular. Emergentist solvable modular maintains that, even if, say, all the modules of an individual are a certain gender (say, male), the person as a whole can still be a different gender (which is considered an emergent property indipendent of the properties of each module), whereas the reductionist solvable modular view would deny that. Unsolvable modular maintains that a person's gender cannot be determined as a whole, but only the gender of specific modules, and this seems to be a valid metaview that is perfectly compatible with both conceptions of gender that are currently (2020's) popular on social media and for which many users (on both sides) passionately insult anyone who disagrees. According to the unsolvable modular view of gender, the people who adhere to the view that gender is defined by one's genitals (or alternatively, one's chromosomes), that is assigned at birth, cannot change, and there are two genders (or three if including rare cases), are referring to the gender of a specific module, that is, the "genital" (or "chromosome") module, whereas the people who adhere to mainstream transgenderism (non-mainstream views may vary from the mainstream one, of course) are referring to a different module, that is, generally the "appearance" module, or some other module. They are both correct, they are just referring to different things. According to the unsolvable modular view, a person's gender as a whole cannot be determined, but only the gender of specific modules. The question then merely becomes which module(s) (if any) should be considered the most relevant in a social/legal context, which is a normative (not descriptive) matter, and therefore subjective, though of course there may still be various arguments that favor one module over the others. I may present the various arguments for and against each of the two contemporary mainstream views of gender (binary genitalia-based gender vs mainstream transgenderism) as seen from the perspective of the unsolvable modular view of gender, and see if it brings anything interesting.
This is a more specific version of a larger topic in philosophy, that is, the relationship between a subject and its predicate. In this case, what does it mean exactly that someone "is" male or female (or whatever else). Coming soon, if I feel like it, lol.
There could be many different categorizations:
-One gender (?): humans
-Two genders: male and female, defined mostly by genitals
-Two genders: male and female, defined by self-identification (think transgender culture, except without non-binary)
-Three genders: children before puberty (considered 'genderless' in this categorization), adult males, adult females
-Three genders: males & females (includes children, and adult males and females who are capable of reproduction), adults incapable of reproduction
-Four genders: children before puberty, adult males & females (capable of reproduction), adults who are incapable of reproduction
-Five genders: children before puberty, adult males & females (capable of reproduction), adult males who are incapable of reproduction, adult females who are incapable of reproduction
-Six genders: male children before puberty, female children before puberty, adult males who can reproduce, adult females who can reproduce, adult males who can't reproduce, adult females who can't reproduce
-Three genders: anyone capable of producing sperm that can fecundate an egg ('males'), anyone capable of having an egg that can be fecundated by sperm ('females'), anyone incapable of reproducing (children, sterile adults, old women and others) ('genderless')
-Three genders: male, female, non-binary, and is defined by self-identity (very similar to many forms of modern transgenderism)
-And many, many others.