— Richard Drury/Getty

Whether big or small, a man’s hands say a lot about him. Based on whether a man has strong, calloused palms or long, dexterous fingers, people may make assumptions about his career or hobbies, like whether he does physical labor or plays piano. Whether those stereotypes about male hands hold true, the science doesn’t say. The size of a man’s hand size can, however, reveal a lot about his biology. Studies have shown that whether a man has small hands, big hands, or average hands, male hand size gives away a ton of information about everything from a man’s athletic ability to his sex life and even his penis size.

First, a clarification: When scientists study a man’s hands, they don’t focus much on the actual hand size itself. They’re looking at the proportions of his fingers.

“It has been known by anthropologists for more than 100 years that, compared to females, males have longer ring fingers relative to their index fingers,” says John T. Manning, Ph.D., an honorary research fellow at Swansea University in Wales who has been studying the health implications of finger or “digit” ratios for several decades. In a 1998 study, Manning and his colleagues demonstrated that this difference was consistent throughout childhood and likely a result of how much testosterone they were exposed to in utero. This, in turn, influences many behavioral, health, and anatomical outcomes throughout life for both men and women in different ways.

It turns out men who are overly concerned about the size of their hands should shift their attention to their fingers, much like scientists have been doing. Whether you’re a guy with small hands, large hands, or average-sized hands, the index and ring fingers say a lot more about you than you may realize. But a word to the wise: Anyone who advises you to compare the size of your hand to the size of your face wants you to hit yourself in the face.

Male Hands Say Something About the Penis

Is the old wives’ tale about penis size being proportional to hand size true? You’re damn right it is. In a sense.

One study, published in the Asian Journal of Andrology, revealed that men with longer ring fingers had proportionally longer penises to match. After considering the age, weight, height, digit ratio, individual finger length, and body mass index (BMI) of 144 men, they found that height and the gap between their ring fingers and index fingers were related to penis size.

“Based on this evidence we suggest that the digit ratio can predict the adult penile size,” the study authors wrote. So if you want to confirm what you’re working with, look at your ring finger and how much longer it is than your index, not just how big or small your mitts are.

A Man’s Hands Might Have Something to Do With His Attractiveness

Men with long ring fingers may be more prone to promiscuity because they’re too damn attractive, studies have shown. Although definitely not an excuse for cheating, when researchers had 49 women assess the attractiveness of 49 men, they found that men with longer ring fingers ranked higher than their peers in terms of facial attractiveness. Interestingly, the study authors found that this was only true for facial attractiveness, but not voice or body odor attractiveness.

A Man’s Hand Size Predicts How He’ll Treat Women

Men with longer ring fingers are more likely to smile, laugh, compromise, compliment, and listen attentively to women, according to one study of 78 men and 77 women. The longer their ring fingers, the kinder and more agreeable the men were to the women in their lives, whereas men with shorter ring fingers were a little more hot-headed toward the ladies.

This means that men with more fetal testosterone exposure were surprisingly nicer to women, which seems surprising on the surface given the link between testosterone and aggression. However, past research shows that men tend to be more agreeable to women than other men in general. And men with longer ring fingers have been found to have more children and get sexually excited more easily, so the reason they’re so accommodating may not be chivalry.

Thus, the authors added this caveat: “Whether the lower ratio is associated with agreeableness towards all women or those who want more children or who are more sexually available, could be explored in future research.”

Or, if you consider the previous study, perhaps women are more likely to agree with these men because they’re hot. Speaking of…

Longer Ring Fingers Mean More Sex and Fertility

The same study suggests that longer ring fingers may be linked to male fertility, a finding backed by preliminary research. Other studies indicate that men with longer ring fingers are four times more likely to partner with women who display outward signs of fertility, such as larger breasts and hips and smaller waists. Meanwhile, both men and women who have longer ring fingers may be predisposed to having multiple sex partners, Oxford University research suggests.

A Man’s Hand Size Hints at His Athletic Ability

As if they didn’t seem like nature’s Prom Kings already, men with longer ring fingers have better hand strength, regardless of their age and body size, a team of father-son researchers found. Several other studies echo the sentiment that longer ring fingers are linked with superior athleticism and strength.

“The digit ratio does not directly impact athletic performance, but appears to point to something that may. Pardon the pun,” says Grant Tomkinson, Ph.D., a fitness researcher at the University of South Australia who is understandably the dad-half of the research duo. What’s most surprising to Tomkinson is that men who have this biomarker for more fetal testosterone exposure may “perform better athletically because they experience higher spikes in testosterone when challenged,” he says.

Hand Size Has Something to Do With Cancer Risk

Longer ring fingers aren’t all about looking attractive while winning athletic competitions, and there are some unfortunate health issues associated with excess fetal testosterone exposure.

For one, there’s evidence that men with longer index fingers and shorter ring fingers have a comparatively lower prostate cancer risk, and other studies show that men with longer ring fingers respond worse to treatment and have a worse prognosis overall. Interestingly, the same is also true for women with longer index fingers and shorter ring fingers but in regard to lung cancer.

Sure, fingers are biomarkers and not diagnostic tools, but it does speak to the notion that your health is literally in your own hands.

Longer Ring Fingers Are Linked to Impulsivity Issues

People who have longer ring fingers and shorter index fingers are more prone to ADHD, alcohol dependence in men, as well as cannabis and heroin addiction. “The evidence is quite strong for these conditions,” Manning warns. So if you or someone you know tends to make poor decisions swiftly, look to these fingers. But be warned, this will be an unwelcome party trick.

Hormones May Make Men and Women Have Different Finger Lengths

Men generally have longer ring fingers than index fingers, but for women it’s the opposite. There are two major factors that could be the cause. It could either be that people with longer fingers (which just happens to usually be men) are more likely to have longer ring fingers. Or exposure to different levels of sex hormones in utero could be the cause.

A study of 3,802 men and 3,780 women disproves the first hypothesis by finding that there isn’t a correlation between total finger length and whether the index or ring finger is longer.

Although this finding isn’t going to give you any insight into your personality or health or penis size, it does support just how important prenatal sex hormones are in determining finger size. And this goes on to influence a lot of other aspects of a man’s life.

Finger Length Is Linked to COVID Risk

In another preliminary study, Manning and his team found that people with relatively short ring fingers compared to the rest of their digits are more likely to get severe COVID and be hospitalized. This was true regardless of sex. Even more striking was that people whose index finger to ring finger ratio and middle finger to little finger ratio were different between their left and right hands had a substantially higher risk of hospitalization.

Although longer index fingers and shorter ring fingers are linked to lower fetal testosterone exposure, researchers believe asymmetry between the two hands is related to “developmental instability.” Since child development is supposed to follow a pattern that lends itself to symmetry, “deviations from symmetry are thought to be markers for instability in the developmental process,” Manning explains. This instability can come from poor diet, parasites, and other stressors early in life that could make individuals more susceptible to a range of pathogens as adults.

Elderly men are at the highest risk for severe COVID, and they have lower testosterone as a result of aging. So, it makes some sense that lower testosterone combined with asymmetry is likely what contributes to the highest risk.

More research needs to be done, but “the implications are most important for public health issues rather than individual responses,” Manning adds. In other words, if you’re worried about severe COVID, don’t look to your hands for answers like some palm reader. Use those fingers to call the doctor, not to play one.