Fact checking Donald Trump's claims about his penis size

Donald Trump wanted to make one thing very clear during Thursday night’s Republican debate: He does not have a small penis.

Of course, The Donald is known to stretch the truth a little, so we decided to fact check whether or not his claims stand up to science.

First things first, though. Why did Trump feel the need to talk about his d**k during a presidential debate? Well, earlier in the week, during a campaign speech, fellow candidate Marco Rubio pointed out that Trump is known for having small hands (allegedly). Then Rubio said, “And you know what they say about guys with small hands.” Get it? They have small penises!!!! AHAHAHA. These guys want to rule America.

Anyway, come Thursday night, Trump—again, debating to be the leader of the free world—decided to set the record straight on national television by holding up his hands and making sure everyone saw just how big they were.

“Look at those hands,” Trump said during the debate. “Are they small hands? And he referred to my hands—if they are small, something else must be small. I guarantee you there is no problem. I guarantee you.”

So … could Trump’s hands actually be linked to how large his penis is? (He’s the one saying it—not us.) What does the scientific literature have to say about the ‘ol hand size rumor?

Turns out there are no good studies on the correlation between hand size in general and penis size. (I know, I know, somebody find a group of scientists to give a research grant to STAT.)

However, a 2011 study published in the Asian Journal of Andrology, an international peer-reviewed publication, did find a correlation between finger size and the male member—specifically, the ratio between a man’s index finger and his ring finger (known in the science world as the 2D:4D ratio). In the study, researchers in South Korea found that the lower the ratio between the two digits, the longer the man’s penis. In other words, the longer a man’s ring finger is compared to his index finger the longer his penis.

Scientists hypothesize that 2D:4D ratio is indicative of how much testosterone men were exposed to in the womb. This ratio has been linked to other things such as sperm count and coronary heart disease.

I should note that the measurements are too small to be noticeable to the naked eye, so whether or not Trump’s finger ratio put him in the longer penis or shorter penis category is up to him to reveal.

Other than finger size, studies have looked into foot size and physique as an indicator of penis size, but no noteworthy trends have emerged—on the contrary, several studies have found that neither correlates with whether or not a man will be packing. One study did find that large buttocks was indicative of a longer penile length in Nigerian men, but Trump is neither Nigerian nor do we want to go there.

So, really, we’ll never know if Trump was telling the truth about his 100% guarantee that he does not have a small penis.

In other news, the relationship between penis size and intelligence has yet to be determined.

Taryn Hillin is Fusion’s love and sex writer, with a large focus on the science of relationships. She also loves dogs, Bourbon barrel-aged beers and popcorn — not necessarily in that order.