The basic rule regarding biological sex is simple and difficult to dispute: A male has a penis, a female has a vagina and breasts.

Even though they undoubtedly exist, cases of people having chromosomes, hormonal profiles or genitals at birth that are not typically male or female (called 'intersex' or 'hermaphrodites') are so rare (28 cases recorded in France in 2017 births) that they can hardly be used as a pretext to question the biological binary Male/Female. The same goes for sex change operations, which, given their number, are a drop in the ocean.

That said, the notion of gender identity goes far beyond the simple physical body. Gender is generally defined by sociologists as a feeling or an internal conscience that leads to adopting a style of behavior generally attributed within the society in which one evolves to one sex or the other by the media, religion, educational, political and social systems. The very definition of gender is enough to detect a big problem: We do not all watch the same media, we do not all have the same religion, we do not all have the same education... So inevitably we cannot agree on a strict definition of the 'Masculine' gender or the 'Feminine' gender.

To use the concept of 'masculine' and 'feminine', we must therefore attribute to them the 'cliché' images accepted by the majority. Let me explain the term 'cliché': Let's take fear, for example. For many people, women are more likely to be afraid than men. However, scientific studies have shown that this is false, that there is no major difference! But if we must attribute characteristics to the 'feminine' gender, we must nevertheless include fear because that is how the majority will define it, even if it is false, hence my characterization of 'cliché'.

Once the previous paragraph is well understood, we can consider that the 'Masculine' Gender implies being fearless, dominant, aggressive when necessary, liking competition and obeying the hierarchy. Conversely, the 'Feminine' gender includes being cautious or even fearful, submissive, preferring dialogue to confrontation, collaborative work to competition and negotiation to blind obedience to the leader. This is how we define a Man or a Woman in our society.

If biological sex and gender identity match, we speak of 'Cisgender' (a word that is rarely used, we rather say 'Normal') and otherwise 'Transgender'.

For a long time, it was believed that there were only two genders: masculine or feminine. This was referred to as the 'binary' model. However, over time and through psychological studies, it was realized that some people do not have a majority of masculine or feminine characteristics and should therefore be assigned a 'different gender' (which can have many names). In this case, we speak of the 'non-binary' model.

My Opinion :It seems quite obvious to me that if there are fearless, dominant, virile men, in short what we often call 'Alpha males', there are also fearful and withdrawn men who prefer to follow rather than lead. And it's the same with women. But it also seems obvious to me that we have more reckless men (Cf road accidents) and cautious women, so characterizing a behavior as 'masculine' because a majority of men possess it doesn't seem stupid to me AS LONG AS we keep in mind that we are talking about the majority and not the totality AND THAT there is no problem in not being in the said majority...

The idea is not new since in some cultures, there were officially four genders (Masculine Man, Feminine Man, Masculine Woman and Feminine Woman). Feminine men stayed to take care of the children and the camp while masculine women participated in hunting and fighting. Some may however say that it remains perfectly binary in fact, the masculine goes to hunt and the feminine stays at the camp, it's just that they do not use the criterion of biological sex to distinguish them but more a criterion of efficiency in tasks, which seems logical in terms of survival (An ideologue will keep a very physical woman in the kitchen and send a sissy to fight because "she's a man" when the survivalist will do the opposite).

Regarding the limitation to only two genders, I see two problems. First, if we consider gender as a slider that varies from 'Very masculine behavior' to 'Very feminine behavior', it implies a central position, much like there is 'Androgynous' in the middle of Masculine Appearance / Feminine Appearance. Second, just as there is a term 'Bisexual' for those who sleep with both men and women, it would seem to me that there is a gender term for those who can present a 'Masculine' gender at times and 'Feminine' at others. This already gives four genders instead of two, but certain things complicate the analysis even more.

If gender identity is an indicator linked to behavior, we have a second indicator called 'Gender Expression' which concerns the external signals that we voluntarily send to others (We are naturally courageous or fearful but we choose to have long or short hair...). Gender expression therefore concerns what we choose to wear (clothes), the language and attitude we choose to adopt as well as our appearance (hairstyle, makeup but also hormone intake or surgery).

My Opinion: Far from being an unnecessary complication, this 'gender expression' factor seems essential to me because gender expression is not necessarily correlated with gender identity.

Exemple 1: One can very well be a woman (Biologically speaking) who presents behavior corresponding to the 'Feminine' gender archetype but who appreciates having a masculine appearance (Masculine gender expression) because one finds it more practical for daily life.

Exemple 2: One can very well be a woman (Biologically speaking) who exhibits behavior corresponding to the 'Masculine' gender archetype but who appreciates having a very feminine appearance (Feminine gender expression) because it helps her to manipulate men and have power over them.

Finally, we must take into account that some people may have a neutral gender expression (Agender) consisting of avoiding any clothing or signal that is too typically masculine or feminine, or a Bigender expression when we mix typically masculine elements with others that are typically feminine.

The fourth criterion of differentiation is sexual orientation. In the humanities and social sciences, sexual orientation is an enduring pattern of sexual attraction to the opposite sex, the same sex, or both sexes. Asexuality (the absence of sexual attraction to others) is sometimes identified as the fourth orientation.

My Opinion: I think this criterion is completely independent of the other 3 (in fact each criterion is independent of the other three). It is the lack of understanding of this point that leads to all the shortcuts like 'transvestites are homosexuals, whether openly or repressed' or 'a girl dressed as a man is a lesbian, whether openly or repressed'...

So of course, managing 4 criteria that can each present 4 positions is more complicated than the simplistic "If you have a dick you're a guy, otherwise you're a girl and you must then act according to the expected model" but hey I hope that all my readers are part of the human group who think that the mind is a complex thing, very complex and that reducing it to a binary choice is totally ridiculous! Afterwards I am much more perplexed about the interest of giving a name to each of the 256 possible combinations!!!! Already there is not much interest in wanting to put people in boxes but above all we will always have nuances, changes that make the exercise useless. It is much more productive, in my opinion, to understand the different existing cursors and to admit that there are therefore very many ways of behaving towards Gender without it being useful to validate some and criticize others!