Sexual Health > Sex

The Facts About Sex

Everything you always wanted to know about intercourse (but were afraid to ask).

top of red tinted bed with snow falling in red circle on pink background
Illustration by: Illustration by John Munoz

We know sex has been around since before humans. In fact, we are all evidence of sex as the basic tool for procreation.

But whether it's for reproduction or the simple sake of expressing and experiencing pleasure, sex is one of the many pillars of the human experience. Let's discover more about this universal act.

What is sex?

Historically and biologically speaking, sex refers to the transfer of reproductive material from one organism to another for the sake of reproduction. However, our understanding of sex is now infinitely broader

Generally speaking, sex happens when a person engages in sexually arousing activity with themselves or someone else. What constitutes a sexual act is unique to each individual and can differ depending on factors such as sexual preferences, cultural or religious beliefs, and physical capabilities.

How do people have sex?

There are countless ways to have sex, and what type you engage in depends largely on your sexual preferences and whether you're seeking pleasure by yourself or with a partner. 

Although society largely recognized sex as penis-in-vagina penetration for centuries, that's no longer the case. People also may have sex through self-masturbation or mutual masturbation with a partner, penis-in-anus insertive sex, rubbing bodies together, the use of sex toys for insertion or external stimulation, watching porn solo or with a partner, and giving and receiving sexual stimulation orally.

Of course, those are only some common methods of having sex. The sky's the limit. Using a little creativity and exploration, there are endless variations and new ways to explore your sexuality. As long as there's consent from everyone involved, that's OK.

The evolution of sex

Historically, the cultural attitude toward sex has been that it should be classified as a means to an end, with the ultimate goal being reproduction.

However, as humans enter puberty, they soon discover sex has an important role as a method of experiencing physical pleasure and creating intimacy and closeness with another person.

Even as a profession, sex work can be documented all the way back to ancient Greece and Rome. And while prostitution was viewed by society as an acceptable professional role in the Middle Ages, it is now considered taboo in many cultures.

Present-day views on sex are considerably varied. They range from ultraconservative to extremely liberal, depending largely on a person's cultural and religious upbringing. Some experts attribute the split in views toward sex to its omnipresence in society in combination with inconsistent sex education among different demographics and populations.

Sex education in the U.S.

Sex education had its origins in the United States more than 100 years ago when public schools began handing out pamphlets to educate students about pregnancy and the mechanics of reproduction.

In 1918, Congress passed the Chamberlain-Kahn Act, which created the venereal disease division of the U.S. Public Health Service. This legislation was important because it provided education about sexually transmitted infections (STIs) to soldiers fighting abroad in World War I.

Fast-forward to the 1960s when sex education leaned heavily toward promoting an abstinence-only approach to sex, with few details of the ins and outs of sex itself. The fear at the time was that too much information might lead to riskier sexual behavior by teens.

In 2007, a congressionally mandated study on abstinence-until-marriage programs was conducted and concluded that the approach did not have any beneficial impact on the sexual behavior of young people. President Barack Obama increased funds for comprehensive sex education in 2009, establishing two initiatives: the Teen Pregnancy Prevention Program and the Personal Responsibility Education Program.

The Centers for Disease Control and Prevention (CDC) reported that quality sexual health education programs should teach students how to:

  • Access medically accurate health information, products and services, for example, HIV/STI testing
  • Analyze family, peer and media influences that impact health
  • Effectively communicate with family, peers and teachers about issues that are related to or can impact health
  • Make informed and thoughtful decisions about their health
  • Assume responsibility for themselves to improve their health

Though sex education in America has come a long way—and seems to be moving toward a more comprehensive curriculum—studies have shown that fully informative sex education is inconsistent across the country, state by state.

Sexual reproduction

Sexual reproduction occurs when gametes—sperm and egg—come together and fuse parental genomes into a new genotype. In other words, sexual reproduction happens when a sperm fertilizes an egg, creating an embryo. After about eight weeks, the embryo is developed enough to be considered a fetus.

An egg can be fertilized through insertive sex in which the penis enters the vagina and releases sperm that travel the reproductive tract to find and fertilize an egg.

However, with the advancement of medical technology, this fertilization process can now also be achieved through methods such as in vitro fertilization (IVF), intrauterine insemination (IUI) and intracytoplasmic sperm injection (ICSI).

Sexual systems

The male and female reproductive systems are responsible for sexual reproduction.

The female reproductive system consists of internal body parts such as the vagina, cervix, uterus, ovaries and fallopian tubes. The external parts include the labia majora, labia minora, clitoris, vaginal opening, hymen and the opening of the urethra. Together, this system is responsible for the menstruation cycle, the production of female sex hormones and reproduction, and the release of urine.

The male reproductive system comprises the penis, scrotum, testicles, epididymis, vas deferens, prostate gland and the opening of the urethra. This system is responsible for producing and sustaining sperm, discharging sperm, creating and secreting male sex hormones, and the release of urine.

Sex and gender

Though the terms sex and gender are often associated with each other and sometimes used interchangeably, the always-evolving and modern understanding distinguishes the two like this:

Perhaps a more helpful way to think of it: Your sex is assigned based on your physical genitalia at birth, whereas your gender is decided based on what's in your brain.

Essentially, just because a person is born with a certain set of biological characteristics does not mean they have to express or present themself as the gender with which those characteristics are traditionally associated.

Broadening and deepening this understanding as a society is a key step toward destigmatizing nonbinary and transgender individuals as they express and present themselves as the gender with which they identify.

Sexual dysfunction

Everyone deals with occasional problems related to sexual libido or their ability to perform or orgasm every now and then. But if you start to have recurrent difficulty with sexual response, desire, orgasm or pain during sex—particularly if it causes personal distress or relationship strain—then you may be experiencing sexual dysfunction.

Dysfunction can include a decreased level of sexual desire or difficulty reaching orgasm. In women, it can include vaginal dryness or pain during sex. Men with sexual dysfunction may have problems with erections, orgasms or ejaculation.

The symptoms you experience most often depend on the underlying cause of the issue.

If you experience persistent symptoms of sexual dysfunction, consult your doctor. Together, you can work to pinpoint the cause of the dysfunction. Fortunately, there are treatments available for sexual dysfunction for all sexes and genders.

Benefits of sex

Not only does sex feel great, it also can be good for your mind and body. In fact, regularly having safe and pleasurable sex can help your brain regulate hormones and release hormones that improve overall mood and other bodily functions.

For example, when a person orgasms, their brain releases a flood of hormones—including oxytocin, dopamine and serotonin—all of which have the effect of increasing the feeling of intimacy and closeness with your partner, improving mood and even aiding in better sleep.

Aside from the hormonal benefits, the physical act of having sex can be a healthy form of exercise, too.


Having a good understanding of your sexuality begins with education. No one knows it all, but by cross-referencing resources online and developing questions for your primary healthcare provider, your path to a healthy sex life can be more positive. Sex is a contentious subject in the U.S., and knowledge can help you navigate the pitfalls.

Here are some good reference points to start with:


Is it beneficial to have sex?

Not only can having sex provide pleasure, it can also serve as a good source of physical exercise. Additionally, an orgasm triggers the release of several hormones—including oxytocin, dopamine and serotonin—that have been linked to improved mood, better sleep and a heightened sense of closeness and intimacy.

Can I have sex daily?

Men experience a refractory period immediately after orgasm—typically lasting anywhere from just a few minutes to a couple of hours—that must pass before they're able to activate the sexual response cycle again.

Women are able to have multiple orgasms in a row.

As long as you're practicing safer sex, it is perfectly healthy to have sex daily or even multiple times a day.

Why do we have sex?

The reasons for having sex vary depending on who you ask. For some people, sex is merely a means to an end, part of the reproduction cycle with the goal of having babies. For others who may or may not want children, sex is something that brings them pleasure and a feeling of closeness to their partner. Some people may engage in sex as part of their work.