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What Defines (Having) Sex?

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Reviewed by Dr Katherine Hertlein,
created by Blueheart
created by Josh Green
created by Sophie Browness
Date published:
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Photo of Dr Katherine Hertlein
Reviewed by Dr Laura Vowels,
created by Blueheart
created by Josh Green
created by Sophie Browness
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  • The question of exactly what defines the act of sex or sexual activity is not clear cut. In fact, the definition can even vary between sex partners.
  • The Oxford English Dictionary definition suggests: “physical activity between two people in which they touch each other’s sexual organs, and which may include sexual intercourse” - but this is open for interpretation.
  • What we believe about sex and the way we feel about it may depend on our lived experiences.
  • One study found that when men or women were considering the actions of a partner, they were more likely to define particular behaviors as sex if they had taken part in those activities themselves. 
  • It's completely normal to suffer challenges in even a healthy sexual relationship. It's thought that a broad definition of sex gives you a better chance of overcoming these setbacks. 

What is sex anyway? Have you ever actually stopped and thought about that question?

Penile-vaginal intercourse? Tick. Penile-anal intercourse? Tick? Manual stimulation? …no? Oral stimulation? Er…no…yes…maybe? Does it make a difference if one or both partners orgasm? What if a condom is worn? Is sex the same as sexual activity, or different? 

It’s tricky isn’t it?!

According to the BMJ, a major study of sexual behavior among Americans came up with 41 definitions of what “having sex” actually means (1). While an older survey conducted by the Kinsey Institute for Research in Sex, Gender, and Reproduction Studies asked a random stratified sample of 599 students, ‘Would You Say You "Had Sex" If . . . ?’. Findings supported the view that “Americans hold widely divergent opinions about what behaviors do and do not constitute having "had sex."

So rest assured, you’re not the only one who is not sure whether your romantic encounters count as sexual encounters.

Official definitions of sex?

Let’s consult the Oxford English Dictionary to see what they say.

According to the OED online, sex is defined as:

“physical activity between two people in which they touch each other’s sexual organs, and which may include sexual intercourse”.

So this suggests sex may include sexual intercourse, but doesn’t necessarily have to. And there are, of course, a broad spectrum of activities that fall under the category of ‘touching each other’s sexual organs’.

It’s hardly surprising then, that what constitutes ‘sex’ to one person might not be considered as such by their sexual partner.

But perhaps it’s not that simple.

Could it depend on our experience?

Imagine you grew up in a household where sex was treated as something secret and sordid, shrouded in mystery and never discussed. Maybe you did. It stands to reason that with that background you might view a broader spectrum of sexually related activities as ‘sex’. Alternatively, you might see things as extremely black and white, believing that for heterosexual sex to occur a man must put his penis into a woman’s vagina.

Conversely, if you began experimenting young and consider you have a large breadth of sexual experience, you might feel you’re in a better position to assess and define various activities as ‘sex’ or ‘not sex’. You might define fewer activities as ‘sex’ simply because they’re more normalized in your lived experience.

Equally, we can assume that context plays a part.  

A 2015 study published in the Journal of Sex Research (3) found that “both men and women were significantly more certain that a behavior counted as "having sex" when considering their partner's behavior outside the relationship than when they considered their own behavior”.

Put simply, you’re more likely to think of a particular activity as ‘sex’ when you’re faced with the idea of a partner doing it with someone else, than you are if you’re doing it yourself.

Does the exact definition of sex really matter anyway?

In a word, no. It completely depends on you and your partner. As a couple, you get to throw the rule book out the window and decide what does and doesn’t feel good to you. That is, of course, as long as you are both consenting adults and you’re keeping yourself protected and safe.

Whether it’s foreplay, long-distance sex, scheduled sex or completely and wonderfully spontaneous sex, what happens and how you define it is up to you. What matters is the physical pleasure you enjoy and the level of connection you achieve with your partner.

As experienced sex therapists, we find that, in practice, a broader definition of sex tends to be associated with better outcomes in the couples we meet. Where people believe that a greater variety of activities and intimacy-building events are included in their sexual relationships, they tend to attribute greater levels of satisfaction to it.

It’s to be expected that, in a healthy relationship, couples will face challenges over time. Sexual desire will ebb and flow in both partners, children or work might get in the way, or life might just have other ideas.

When it comes to working through these issues, the ability to adapt, be flexible and get creative in the way you approach sexual pleasure can make a huge difference. A narrow definition of ‘sex’ could hinder your chance of finding a way around problems. Whereas a broad definition will give you lots of options to ensure you can continue to enjoy a healthy sex life and fulfilling physical relationship no matter what the future holds. 

(1) Tanne, J.H., 2010. Study comes up with 41 definitions of what" having sex" means. BMJ: British Medical Journal (Online), 341.
(2) Sanders, S.A. and Reinisch, J.M., 1999. Would you say you had sex if...?. Jama, 281(3), pp.275-277.
(3) Sewell, K.K. and Strassberg, D.S., 2015. How do heterosexual undergraduate students define having sex? A new approach to an old question. Journal of sex research, 52(5), pp.507-516.
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