Up until quite recently in history, the terms “sex” and “gender” were considered interchangeable words that referred to the differentiation between male and female. However, in today’s world, “gender” is more commonly referred to as a social construct that encompasses gender roles and one’s projected appearance. While there are, in the most simplified manner, two biological sexes that are universally recognized, there are several different gender identities based on how a person presents themselves. This spectrum of gender is due to an internal awareness of personality and identity. Thus, different gender-based pronouns are used to refer to people.
Biological sex and gender identity are two different things. While some may believe that gender and sex mean the same thing, the two are different because they reflect different aspects of a person. Sex refers to the biological difference between male and female structures, whereas gender refers to one’s presentation and projection of identity in society.
Biologically speaking, most people are born either male or female, with either an X and Y chromosome or two X chromosomes. Although many recent developments in medical research have found that biological sex is much more complex than a simple binary differentiation (for example, some children are born intersex, which means they are born with structures that neither match a typical male or female structure), many still believe that there are only two biological sexes. Regardless of biological sex, though, gender identity refers to an individual's societal role and appearance; not genitalia and reproductive organs.
Many people choose to identify with a gender that matches their biological sex. They present and refer to themselves as someone who associates with that particular gender*. But, some individuals identify with a gender that does not match their assigned gender based on their biological sex at birth, and that is also an individual's innate right**.
Biological sex should not be used as an argument that invalidates gender identity because gender identity is independent of whether or not you have male or female genital structures. Additionally, the fact that gender identity is shaped by social constructs, personality and awareness doesn't make it less quantifiably valid than biological sex. It's associated with social science and psychology, both of which have measurable impacts, and can also be affected by biological factors such as hormones or genes. There are strong gender roles that have been established over thousands of years of human development, and the majority of humans have evolved to, for the most part, accept only two different genders. There is a heavy social pressure to have your gender identity conform to the biological sex you were assigned at birth. Nevertheless, not everyone is comfortable identifying in a way that corresponds with their sex, and they should not feel forced to do so. Everyone deserves to have the freedom to live in a way that makes them feel comfortable.
Some of the most common gender identities are agender, androgynous, genderfluid, transgender, and non-binary***. The pronouns that individuals prefer reflect their gender identity, and how they wish to be viewed****. A non-binary individual who was assigned female at birth may prefer the pronouns “they” and “them”, and may present themselves in a way that expresses gender ambiguity. A transgender woman who was assigned male at birth may prefer to be called “she” and “her”, and she may present herself in a way that shows her femininity. Just because she was assigned male at birth does not mean her femininity is less valid, and the pronouns that she prefers are part of how she expresses her gender. Maybe she chooses to receive reconstructive medical procedures in order to reassign her biological sex as well, but this procedure is not necessary to make her gender identity valid, nor is it appropriate to tell her that she isn’t female unless she undergoes this transition. Her physical genital structure is nobody’s business but her own.
If you recently changed your name to reflect your identity, be patient with friends who are getting used to it. If there are people around you who struggle to understand your gender identity but are genuinely interested in learning about it, explain it to them. If one party is willing to show you respect, the best thing to do is reciprocate it. Additionally, if someone you know was born with the biological structure of a "female", but identifies as "male", the appropriate and respectful thing to do is to refer to them with the pronouns “he” and “him”. If you know someone who formerly identified as "male" but discovered they were non-binary later on, it does not mean you can refer to them with male pronouns because they are not male.
If you have a friend who changed their name because they want it reflect their identities, take the time to learn it, and soon enough you’ll use it regularly. If you don't know someone’s preferred pronouns, all you have to do is ask them. It is not difficult to be respectful and polite.
The most important thing, above all, is to respect the uniqueness of every individual. Whether or not one agrees with the fact that there are more than two gender identities, or that "gender" and "sex" differ, we can all agree that the world is a better place when we treat one another with kindness and respect.
*Someone whose gender identity matches the sex they were assigned with at birth is known as cisgender
**Someone whose gender identity does not conform to the sex they were assigned with at birth is known as transgender
***Agender: does not identify with any gender; Androgynous: appearing partly male and partly female and/or having an indeterminate sex; Genderfluid: does not identify with a fixed gender; gender identity fluctuates; Transgender: identifies with a gender that is different than than one given at birth; Non-binary: Does not identify with either of the typical “binary” genders (male or female)
****There are several different pronouns that can be used to refer to individuals who do not identify with either side of the gender binary, such as ze, hir, xi, and e.