How You Can Tell Whether a Sex “Expert” Is Legitimate

March 6, 2019 by Justin Lehmiller

Gizmodo recently published an exposé on Daniel Sendler, someone who presented himself as a sex expert to the popular media and succeeded in getting a lot of publicity for himself over the last two years. However, as Gizmodo reports, Sendler was a “serial fabulist” who misrepresented his training and credentials.

The Sendler case got me thinking about how journalists and consumers alike can tell the real scientific experts from the fake ones. I tweeted a few thoughts on this the other day, but wanted to expand on some of them here.

Verifying someone’s credentials is, of course, a good place to start—but you need to go beyond looking at what their personal website or social media pages say. For example, if they claim to hold a certain license or certification (e.g., AASECT certified sex educator or therapist), you can often look that up on the licensing body’s website. If they claim an academic affiliation, you can easily verify that by visiting their departmental or university webpage. If something isn’t checking out, you could consult with other people in the field (e.g., co-authors on papers or grants, thesis/dissertation advisors) or simply ask that person to provide verification (it’s easy enough to snap a photo of a diploma or certificate).

You can also look at how this person talks—in particular, pay attention to how often they make broad generalizations when they speak. By this, I mean statements along the lines of “X always causes relationship problems” or “when it comes to sex, men want Y and women want Z.”

The more of these sweeping generalizations you hear, the more cautious you should be about accepting what this “expert” has to say.

If being a sex scientist has taught me anything, it’s that there are no universal rules or principles about anything. If you look at any given study, you’ll see a lot of individual variability. Underneath the broader trends, it’s important to be mindful of the fact that there’s a lot of variation in responses. While a trend might tell us what a certain group of people does on average, it doesn’t tell us how everyone in that group thinks or feels.

Even in cases where a trend seems to be robust, it’s still important to be cautious about generalizing it broadly because all scientific studies have limitations. For instance, most sex studies are based on convenience samples of college students rather than representative samples of the broader population. In addition, we’re grappling with a “replication crisis” in science, in which many findings just aren’t holding up when scientists attempt to repeat them. Consequently, a single study supporting a given claim needs to be taken with an appropriate amount of caution. True scientific experts will be mindful of these limitations and cautious about going beyond the bounds of what a given study can tell us.

Instead of making sweeping generalizations and oversimplifications, the people I consider to be the true experts on sex and relationships use a lot of tentative language. For example, instead of saying “always” and “never,” they’ll say “more likely” or “less likely.” They’ll also acknowledge that variability exists and that what works well for one person might not work so well for others. They’ll also be mindful of the fact that any studies they mention are limited and that we usually need more research.

In short, you can often tell whether someone really knows what they’re talking about simply by listening carefully to their choice of words. You’d do well to tune out the overgeneraliers and, instead, look for folks who have nuanced stories to tell.

Want to learn more about Sex and Psychology ? Click here for previous articles or follow the blog on Facebook (, Twitter (@JustinLehmiller), or Reddit ( to receive updates. You can also follow Dr. Lehmiller on YouTube and Instagram.

Image Source: 123RF/iqoncept

Post Featured Image
Written by
Dr. Justin Lehmiller
Founder & Owner of Sex and Psychology

Dr. Justin Lehmiller is a social psychologist and Research Fellow at The Kinsey Institute. He runs the Sex and Psychology blog and podcast and is author of the popular book Tell Me What You Want. Dr. Lehmiller is an award-winning educator, and a prolific researcher who has published more than 50 academic works.

Read full bio >