What is the difference between sex and gender identity?

Sex is your biological sex. What you were born as. Meaning physically what body parts you have. What chromosome is in your DNA. Gender identity is what gender you identify as. Gender stereotypes meaning men are masculine and women are feminine are entirely man made social constructs. Be who you are and don't live your life in a box. You're beautiful just by being true to who you are.

Your sex as male or female is a biological fact that is the same in any culture (most of the time it's just the what you're assigned from birth). Gender is the way you act/dress/..., it can either be masculine or feminine or something else/in between.

Gender identity is what you feel like,feeling feminine/masculine/both/none (yes you can feel stuff like that) but sex is just your physical body,(what's between your legs or other body parts)

This is a tricky one. Usually we would say that sex refers to a person's physical, biological characteristics such as chromosomes and genitalia, while gender identity is the person's sense or idea of their own gender (this may or may not include what their body should look like). But trans people have had their gender identities invalidated so often by people who say something like, "But you're really a [whatever] because your body is [whatever]" that a lot of them now say that their sex is actually the same as their identity, and will get very upset and offended if anyone says it isn't. So basically, they're just words, and they have different definitions depending on who you're talking to.

gender identity is incredibly complicated and can fall anywhere along a vast spectrum (or nowhere on the spectrum at all!), and is entirely at the discretion of the individual - no one else can tell you how you identify. biological sex is only relevant when discussing medical matters, but has no relation to gender identity. the sex you are assigned at birth does not indicate your gender identity, and should not be used to make assumptions about someone's gender identity.

Well, I would say "sex" is what you are born with, let's say you are born with male genitals, then your sex would be male. But then that baby grows up to identify as a female, then their gender identity would be female but their sex is male

A person's sex is their anatomy, so the body parts they have. The two truly recognized sexes in the mainstream world are male and female; however, intersex is more commonly recognized as of lately. Gender identity is a person's internal makeup, and I like to think of it as one's relationship with masculinity and femininity. Someone might identify strongly with one, with both, with none, with something completely different, etc. Those really are just basic explanations to summarize sex and gender identity, and they definitely don't cover everything, but hopefully it gives you a basic understanding as to what these are!

Sex is what bodily features someone is born with. We typically use AMAB (assigned male at birth) and AFAB (assigned female at birth) to describe two sexes. Gender, on the other hand, is constructed by society and by the individual who lives the said gender. Gender doesn't necessarily have to coincide with sex. People who's gender is not in accordance with their sex are called Transgender people. People who believe that their gender is neither binary male nor binary female are called nonbinary people, genderqueer people, etc. An important thing to note is that everyone is valid regardless or sex or gender identity.

Sex is based on your biology, mainly chromosomes and physical organs. Gender identity is more of someone's own personal perception of who they are/where they fall on the gender spectrum.

Sex is more the 'gender you are born with' sorta, Gender is when you feel what gender you are, like with the gender similar to your sex (CIS), or you feel more like a guy more than a girl (FTM) (Male to Female if it was the other way around), and there are people where they feel like neither or they switch between genders daily (Nonbinary and Genderfluid). Some may not even feel like a gender, which is Agender. And there can be sorta 'in between' scenarios that I don't know much about myself. But remember, if someone is preferring a gender that's different from their sex, it is not a choice. A lot of people argue that being trans or agender or beyond the gender identity spectrum that "they made it up" or "they're going through a phase or confused", when they are not, it's who they are.