What We Learned About Sex in 2023

By Dr. Justin Holidays take a look back at four of the most interesting and fascinating things we learned about the science of sex and relationships this year

This year has been memorable for a lot of reasons, not the least of which is that we learned many new things about sex! So, as we get ready to say goodbye to 2023, let’s take a look back at four of the most interesting and fascinating things we learned about the science of sex and relationships this year.

Spontaneous Sex Isn’t More Satisfying Than Planned Sex

A set of studies published in the Journal of Sex Research in February looked at people’s beliefs about spontaneous versus planned sex, as well as how each of them are associated with sexual satisfaction. When participants were asked generally about the extent to which they agree with statements such as “sex with my partner is most satisfying when it occurs spontaneously” and “sex with my partner is most satisfying when it is planned ahead of time,” people were more likely to endorse the belief that spontaneous sex is superior. However, in one of the studies, couples were asked to complete a survey each day for three weeks in which they reported on their partnered sexual behaviors and were asked to indicate whether each sexual event that occurred was spontaneous or planned. What the researchers found was that, no matter whether the sex was spontaneous or planned, neither one actually predicted greater sexual satisfaction!

In other words, while we might be tempted to assume sex is necessarily going to be better when it occurs spontaneously, that isn’t necessarily the case. Generally speaking, couples in this research seemed pretty content with the sex they had, no matter how it happened. So don’t get too hung up on the idea that sex has to be spontaneous in order to be good. The quality of the sex we’re having has more to do with other things, such as the connection we feel with our partner, the quality of sexual communication, and the degree to which our sexual needs are met.

When It Comes to Dildos, Bigger Isn’t Necessarily Better

When It Comes to Dildos, Bigger Isn’t Necessarily Better

In another February study from the Journal of Sex Research, a team of researchers analyzed data from one of the largest online sex toy retailers in the world. Specifically, they looked at hundreds of products listed for sale under the “dildo” category to see if any distinct features of these toys (including their size) were linked to their popularity among customers of the site. It turned out that the length of the toy was unrelated to its popularity. In other words, longer toys weren’t necessarily preferred to shorter toys. With regard to girth, it was actually the case that toys with a smaller circumference were preferred to wider ones. It’s worth noting that the average circumference of the most popular toys for sale was actually quite similar to the circumference of the average human penis.

We all know that pornography tends to give the impression that “bigger is better” when it comes to penis size. So it’s interesting to see that when people are shopping for phallic toys and have the ability to go as big as they want, they don’t tend to go for the oversized models on average. While individual preferences can vary widely, many people prefer smaller toys for penetration simply because they find them to be more comfortable than larger ones.

The many fascinating things we learned about the science of sex and relationships this year

AI Just Might Be the Future Of Sex And Relationship Advice

People are turning to ChatGPT for an increasingly large number of tasks and questions, including questions about their intimate lives. But can artificial intelligence actually give decent advice on something so uniquely human? A few studies emerged this year, suggesting that it has quite a bit of potential. In a September study published in the Journal of Sex Research, scientists asked ChatGPT several questions on the subject of sexual consent to see how it fared as an educational tool. The bot provided surprisingly comprehensive and nuanced answers highlighting the key features of consent and the various ways it can be communicated. This points to the potential for AI to help augment or supplement traditional sex education, particularly since most people don’t tend to get great sex ed in the first place!

Going even further, in a recent pre-print article, a team of therapists gave ChatGPT custom instructions to respond to a group of users as a relationship therapist would. Participants then interacted with this “therapy bot” to ask their relationship questions, and they were interviewed by the researchers afterward about their experience and the quality of the advice they received. You may be surprised to learn that participants rated ChatGPT highly across the board, including in terms of its therapeutic skills, “human-likeness,” and ability to provide actionable steps.

None of this is to say that sex educators and therapists are going to be out of business any time soon, but these findings show that even at this very early stage of AI, this technology has the potential to widen access to educational and therapeutic resources that might help us to improve and enhance our intimate lives.

Let's take a look back at four of the most interesting and fascinating things we learned about the science of sex and relationships in 2023

People’s Reasons for Cheating Can Be Counterintuitive

Research on married couples finds that roughly 20-25% of them commit infidelity at some point. And the numbers are even higher when you look at people who are dating. So why do so many people cheat?

The popular assumption is that they’re not happy with their sex life or relationship. And, indeed, that is sometimes what motivates infidelity. However, an April study published in the Archives of Sexual Behavior that looked at people who were seeking affairs online found that poor relationship quality wasn’t actually a major driver behind why these folks were cheating.

In other words, this means that whether people are in happy or unhappy relationships, cheating can still happen. But if you’re in a happy relationship, why cheat? That seems counterintuitive, right?

Well, it’s because affairs aren’t always saying something about the quality of the relationship itself—sometimes, they say more about the person who is cheating. In the aforementioned study, a common reason people in happy relationships were cheating is because they were seeking autonomy or independence. In other words, it was about a search for the self.

Another reason people in happy relationships cheat is that, while they had a satisfying sex life with their partner, they had a strong desire for sexual novelty, variety, or excitement. Simply put, they were just looking for an extra thrill.

Better understanding the reasons and motivations behind infidelity is important because we know that infidelity is one of the biggest causes of relationship turmoil and divorce. So, if you want to prevent that, you need to know why it happens in the first place.


These are just a few of the many fascinating things we learned about the science of sex and relationships this year. Here’s to hoping for another dose of tantalizing insights in 2024!

Let's take a look back at four of the most interesting and fascinating things we learned about the science of sex and relationships in 2023


Kovacevic, K., Tu, E., Rosen, N. O., Raposo, S., & Muise, A. (2023). Is Spontaneous Sex Ideal? Beliefs and Perceptions of Spontaneous and Planned Sex and Sexual Satisfaction in Romantic Relationships. The Journal of Sex Research.

Johns, S. E., & Bushnell, N. (2023). What Drives Sex Toy Popularity? A Morphological Examination of Vaginally-Insertable Products Sold by the World’s Largest Sexual Wellness Company. The Journal of Sex Research.

Marcantonio, T. L., Nielsen, K. E., Haikalis, M., Leone, R. M., Woerner, J., Neilson, E. C., & Schipani-McLaughlin, A. M. (2023). Hey ChatGPT, Let’s Talk About Sexual Consent. The Journal of Sex Research, 1-12.

Vowels, L. M., Francois-Walcott, R., & Darwiche, J. (2023, October 29). AI in Relationship Counselling: Evaluating ChatGPT’s Therapeutic Efficacy in Providing Relationship Advice. https://doi.org/10.31234/osf.io/3zajt

Selterman, D., Joel, S., & Dale, V. (2023). No remorse: Sexual infidelity is not clearly linked with relationship satisfaction or well-being in Ashley Madison users. Archives of Sexual Behavior.

Fincham, F. D., & May, R. W. (2017). Infidelity in romantic relationships. Current opinion in psychology, 13, 70-74.