...I just realized...Actually, neither transgender people nor "non-binaries" exist, nor will they exist. You can feel the opposite sex. You can operate to look like the opposite sex. You can change the shape of your genitals to those of the opposite sex. You can dress with socially designated clothing for the opposite sex. But your set of chromosomes remains the same. You are still female or male. Same, ''non-binary '' people...There are only two genres: Male or female+
+And you are, like it or not, one of them. Why do people insist on that? Why do people insist that you can change something that is inherently impossible to change? You can be homosexual perfectly, because either genre can attract you sexually or romantically, it doesn’t really have to do with whether you feel masculine or feminine, it just has to do with what atracts you. But you can’t avoid being one of the two genders, nor can you change it. You’re still one gender, like it or not.
I am going to break from my usual sarcastic routine for a moment and answer under the assumption that you are speaking in good faith from a place of ignorance, not as a malicious troll. Judging by your spelling errors, I’m also guessing you are young. Perhaps that is my mistake, but I will offer you some patience that you are unlikely to receive elsewhere.
First of all, the idea of “biological sex” is really only useful when referring to reproductive capacity. There’s a whole lot more to human sex and gender than that, which I will get into in a moment.
You may or may not be familiar with the concept of “intersex”. Humans, like virtually all other animals, experience a great deal of diversity when it comes to how sex chromosomes are constructed and expressed. You probably know of XX (”female”) and XY (”male”), but some people may be X, XXY, XYY, XXYY, XXX. These constructions are less common and may be associated with certain complications, but the point is: XX and XY are not the full story, nor some unbreakable rule. Even having “typical” chromosomes is no guarantee of physical development - some people with XY chromosomes develop typical “female” characteristics, including breasts and vaginas, because their bodies do not respond to androgens to a greater or lesser degree. These people may go their whole lives believing they have XX chromosomes. Others may have XX chromosomes, but will not develop wombs and will have typically “male” sexual traits. Still others may develop traits that are “in-between” and resist simplistic classification as “male” or “female” - ex., both functional ovaries and testicles. Some people are even intersex chimeras, possessing DNA that is both XY and XX after the in utero absorption of a fraternal twin’s genetic material. One cell might be “male”, another “female”. I’ve read estimates that as many as 1 out of 100 people have an intersex condition. Common? Well, enough so that rigid, “opposite” understandings of sex are just plumb wrong.
Importantly, intersex and transgender are not the same thing. Some intersex people do ID as trans, and many of the hormonal and surgical treatments they may seek are the same.
“Sex” describes several very different things: chromosomes, genitalia, secondary sexual characteristics, and the physical structure of brains. Sex chromosomes, as I explained, are not completely correlated with physical expression. Genitalia exist on a spectrum of size and functioning. Secondary sexual characteristics, such as hair, breast tissue, voice pitch, and skin type, are dependent on hormones. Brains are where it gets tricky - while there are sexual differences between brains, they’re extremely variable and it’s currently impossible to determine how much of that is genetic, hormonal, or affected by social conditioning.
A transgender person will not be able to change their chromosomes, but they are able to affect the other aspects of sex. Someone with XX chromosomes, who does not have an intersex condition, may take testosterone treatments that will deepen the voice, increase body and facial hair, create male-pattern hairlines, develop muscle, lengthen the clitoris, redistribute fat, halt ovulation and menstruation, and affect the womb and vagina. The hormones will also affect the structure of the brain, whether or not the individual had a “male”-typical brain before treatment. Someone with XY chromosomes who embarks on an estrogen/androgen-blocking treatment will experience fat redistribution, breast growth, possibly lactation, minor voice changes, changes in hair density and texture, halt production of sperm and ejaculate fluid, decrease erectile tissue, shrinking of testicles, ect. They may also develop more “female-typical” brains.
(Related note: external genitalia is developed in response to in utero sex hormones. Ovaries/testes and clitoris/penis develop from the same tissues.)
I want to take a brief moment to talk about a couple of non-human animals, because neat biology facts is kind of my thing, I guess. Honeybees effectively have three genders: drones, males used almost exclusively for sexual reproduction; workers, genetically female but infertile bees which do typical “bee stuff”; and queen bees, which are the mothers of the hive and spend their lives laying eggs. A queen bee and a worker bee are genetically identical - queen bees start off as regular worker larvae but are fed an exclusive diet of royal jelly to induce their sexual development. Very, very rarely, a worker bee will have ovaries just barely developed enough to allow for reproduction under extreme and unstable circumstances, laying only a small handful of unfertilized, genetically male eggs that occasionally live to become drones. It does not make sense to classify honeybees as either “female” or “male”, because genetics end up playing a smaller role than environmental factors.
Also…. chickens! Many cities allow backyard chicken coops, but specifically ban keeping roosters within city limits due to them being noisy nuisances. Most urban coops contain only hens… that is, until one spontaneously becomes a sterile rooster. A hen may slowly transform by growing spurs, a large comb, crowing obnoxiously, and becoming protective of the other hens, and even trying to mate with them. Despite having the DNA of a hen, it becomes a rooster in every way that counts to city officials, your neighbors, and other chickens. (There are many other species that can change sex and become fertile/virile, but I wanted to talk about chickens ‘cause no one else does.)
ANYWAY. At the very least, I think we’ve established that the biology of “sex” is complicated, and perhaps you now understand why “gender” is a separate-but-related concept. If “sex” refers to a mess of DNA and physical traits, then “gender” describes social and mental phenomena. Because we straight-up just invented society and norms, “masculinity” and “femininity” are highly subjective terms and their relationship to biology is… the subject of thousands of years of debate. Really. But we’re social animals, so social constructs are “real” in a certain sense. We are constantly training each other to behave in certain ways from the moment of birth - enforcing some things, discouraging others, molding and influencing each other with cultural expectations. What that means to us depends on the unique cocktail of biological and social experiences of each individual. We are not currently able to give a definitive scientific answer to “why” people are transgender - not that there’s one universal Transgender Experience, anyway. We do know that it’s nothing new, and that we are currently living in an era where science and technology can provide realization to all kinds of needs and desires with relative ease and safety. People’s business is their business. Ultimately, we are little more than neural jellyfish, floating briefly in a sea of mystery. Instead of being afraid of and condemning what we don’t understand or empathize with, we owe each other patience, compassion, and respect.