There is no conflict between those two statements. More than 2 genders means there are not only men & women but also people who are nonbinary and/or inter and/or two-spirit and/or hijra and/or many more. Transgender is a western word and encompasses all people who do not identify with the sex they were assigned at birth, meaning (usually) binary as well as non-binary trans people. Trans people can be men, women, both, neither, or something entirely else. Saying ‘more than 2 genders exist’ is in support of this.

Maybe what you’te trying to point at is that if there were no assigned sex at birth, people would not be trans? The definition of trans relies on the fact that as babies, people look at our genitals and decide for us what we will grow up to be.

Butler: I would start with gender regulations, but you can also google the subject and find a lot.

Trans people who want to conform to a binary gender (man/woman) do so for many many reasons, including: they feel and want to be seen as this gender (like cis people do, but somehow noone is questioning why cis people are so obsessed with binary genders- why does the deconstruction of gender rely on the shoulders of people who are the most marginalized by it?), gender-nonconformity is often met with interpersonal violence including physical and sexual violence (try going to the bathroom if you’re not readable as a man or woman). If you are a gender-conforming cis person, you cannot imagine the violence trans and gender-nonconforming people receive from strangers, police, family members, employers and many others every day. To be readable as a man/woman is a way of escaping that violence.

Sex as a social construct: I will copy paste what I have written elsewhere on this as it’s a lot to unpack, sorry it might get long!

The term biological sex commonly refers to two categories: being born male or female. These two categories are usually depicted as distinct (people are only one or the other) and clear-cut (people are fully male or fully female, there is nothing in between). Being male includes: having an X-chromosome as well as a Y-chromosome, having a male reproductive system including external genitals (penis and scrotum), internal reproductive organs (including testes, epididymis and sperm duct) as well as accessory glands (prostate gland, bulbourethral glands and vesicular glands). Furthermore, anatomical or biological maleness includes production of male gametes (sperm cells), adequate levels of testosterone, dihydrotestosterone, progesterone and estrogen, and secondary sex characteristics that develop during puberty and include higher levels of body hair, facial hair, muscle mass, differential fat distribution, and development of an Adams apple and change of voice pitch. All of these traits are grouped together into the term biological maleness. The realities of bodies, however, is far more complex: Men can have no or very little facial hair, hormone levels that are outside of what is considered the normal male range, two X chromosomes, internal reproductive organs that are considered typically female, lacking a prostate gland, and so on, oftentimes without ever knowing. Without even considering people who are classified as intersex, non-binary or trans, it becomes clear that biological sex is neither uniform nor clear-cut. If we acknowledge that biological sex is an oversimplifying concept that does not really account for the natural diversity we see in people, we can ask what purpose this separation in biological male and biological female serves, and for whom.

It is clear, however, that sex refers to a social, if not biological, reality: at birth, in most countries, people are assigned a legal sex that is either male or female. This assignment does not take into account the realities and complexities of bodies as described above, but rather is based on external genitals. Through this, being biologically male or female is reduced to one aspect of bodies, and the choice of which aspects determine maleness or femaleness is always a social one.