[From STUDY.COM Intro to Sociology: Chapter 8 Sex and Gender in Society; section 1 Defining Sex vs. Gender]

https://study.com/academy/lesson/sex-and-gender-in-society-differences-preferences-characteristics.html#/lesson

Transcript
You might think you know everything about the differences between boys and girls, but this lesson covers less commonly understood topics. After defining sex vs. gender, it covers less common sexual identities, such as intersexed and transgender individuals. In addition, theories on sexual orientation are covered, including both categorical and continuum perspectives of sexual interest.

Defining Sex vs. Gender
Have you ever gone shopping for toys and noticed that in most stores, toys are separated into sections for girls or boys? The girls' section is probably bright pink with sparkly ponies and princesses everywhere. In contrast, the boys' section is usually blue and brown with toys like plastic guns, soldiers and cars. Our society teaches little girls and boys our stereotypical expectations very early on. This lesson focuses on the concepts of sex and gender, then discusses non-traditional forms of gender, such as transgenders. Finally, we'll cover the idea of sexual orientation and how different orientations might be viewed in society.
First, we should define the difference between the terms 'sex' and 'gender.' In most social sciences, sex refers to biological differences between males and females. Biological differences are usually split up into two categories. The first category is called primary sex characteristics, which include internal and external genitals. Put simply, men have a penis and testes, while women have a clitoris and ovaries.

The second category that is used to differentiate between men and women is called secondary sex characteristics, which includes non-genital differences. For instance, there are hormonal differences: Men produce more testosterone, while women produce more estrogen. Men are usually taller and physically stronger than women, have more facial hair and they more often tend to go bald.
In contrast to the biological concept of sex, gender is how masculine or feminine a person feels and how he or she expresses those traits to others. Some scientists state that gender is where you fit on the gender spectrum. Modern gender studies try to avoid defining gender based on gender stereotypes. For example, we used to have stereotypes about men being better at math, enjoying sports and being more stinky and messy than the average woman. And we used to have stereotypes about women enjoying being around children, baking and wearing pink frilly dresses. When you think about your own preferences and behaviors, are you pretty masculine or are you more feminine? This psychological experience of being male or female is gender.

Non-Traditional Genders

Now that we've defined sex and gender, you might not have realized that so far, we've only talked about the concepts in terms of male versus female. Many people do not consider the fact that many people who study these topics acknowledge that there are, in fact, more than two categories of sex or gender. There are two concepts that are important for you to know.
The first concept is that of people who are called intersexed. Intersexed people have an unusual biological makeup that doesn't match either a traditional male or female. For example, traditional men have a chromosome pair we call 'XY,' and traditional women have a chromosome pair we call 'XX.' Did you know that there are lots of other possible combinations? There are people who have three chromosomes, such as 'XYY' or 'XXX.' These people often have genitals that are some kind of mixture, such as a small penis or an enlarged clitoris.

There are other types of intersexed people who have one of the traditional pairs of chromosomes, but their hormones are unusual, such as getting extra doses of testosterone or estrogen when they were fetuses. This results in other types of bodies, such as a body that might have both a penis and breasts. Scientists now acknowledge that because of intersexed conditions, there are really more sexes than just male and female. If you count all the different possible intersex conditions, you might say that there could be 20 different possible sexes, or more.

Another way that people might not match how we traditionally view sex and gender is if they are transgender. Transgender people feel that they are a different sex than the one based on their physical body. So a transgender person might be biologically male, but feel inside that they are really a female. This person might prefer to wear women's clothes, go by a woman's name and date men. It could be the other way around, as well; a biological female might feel inside that a male assignment is more fitting.
Transgender people sometimes take hormones or have surgery to change their bodies to be more in alignment with how they feel on the inside. A similar term you might have heard is transvestite, which refers to people who are comfortable with their biological sex but prefer to wear opposite-sex clothing. Being a transvestite does not necessarily mean that you are also a transgender; they are two different things.

Sexual Orientation

The last topic we'll cover in this lesson on sex and gender is the idea of sexual orientation. Sexual orientation refers to whether you are sexually attracted to men, women or both. Most of the time, sexual orientation is divided into three possible categories.
First, most people identify as heterosexual, which means that you are sexually attracted to people of the opposite sex. In other words, men would be attracted to women and vice versa. An alternative is to identify yourself as homosexual, which means you are sexually attracted to people of the same sex. So here, men are attracted to men, and women are attracted to women. The third option is bisexual, which means you are sexually attracted to both men and women. Note that there are actually more categories than just these three, but most people fall into one of these three groups.

Now, like I said before, most people think of sexual orientation as one of these three categories. However, many people who study sexual orientation actually believe that sexual orientation could not be in categories like this, where you need to pick one of the three options. Another possibility is that sexual orientation could be on a sliding scale.

This idea was popularized by a famous sex researcher named Alfred Kinsey, who conducted thousands of interviews regarding people's personal sexual lives and preferences. Kinsey believed that sexual interest could be viewed as flexible. To explain, think about a continuum for another variable, such as height. On one end of the scale, you have people who are very, very short, and on the other end of the scale, you have people who are very, very tall. People on either end are very unusual, because most people are somewhere in the middle.

Kinsey said the same idea could be applied to sexual interest. You could have a scale where one end was very heterosexual; people only have experiences and interest in the opposite sex exclusively. On the other end is very homosexual; people only have experiences and interest in the same sex. However, Kinsey said that most people will actually be somewhere in the middle. Throughout life, people can move around on the scale. You might be mostly heterosexual, but have a single experience with someone of the same sex, or a fantasy about someone of the same sex. This would move you up on the scale just a little bit.
So in summary, it's possible that sexual orientation is more like a scale that you could move up and down over your life and not a simple category where you're stuck forever. Note that this theory implies that most people are at least a little bit bisexual.

Lesson Summary

In summary, sex refers to the biological differences between men and women, while gender refers to psychological differences, including how masculine or feminine you are. While most people think of sex as only being male or female, there are other possibilities. Intersexed people have an unusual biology that doesn't match traditional male or female biology. In contrast, transgender people have typical biology but don't feel their identity matches their biology.
Finally, sexual orientation refers to whether you are sexually interested in men, women or both. While most people think of sexual orientation as being the categories of heterosexual, homosexual or bisexual, many researchers believe that sexuality is actually more like a continuum or sliding scale that can change through life, and that most people fall somewhere in the middle of the scale, indicating at least a little bisexual interest.

What do you think of these alternative ways to think about sex and gender?