Gaby
A team at Swansea University says our affinity for beer may begin before we’re born.
Ordering another pint can feel spontaneous. But a new study suggests our tendency to drink may be shaped long before birth.
How Was the Study Conducted?
Led by evolutionary biologist John Manning, the team measured the lengths of the ring and index fingers of 258 adult students—89 men and 169 women. They also asked participants about their drinking, recording grams of alcohol consumed per week.
The researchers worked from the idea that everyone is exposed to some testosterone in the womb and that people have different balances of male and female sex hormones.
The results showed that greater prenatal testosterone exposure was linked to higher adult alcohol consumption. Finger length, the researchers say, reflects that prenatal testosterone exposure and therefore how “masculine” someone is.
A Few Words About Professor Manning’s Theory
Professor John Manning is known for his work on the 2D:4D ratio—the relative lengths of the index (second) and ring (fourth) fingers. He argues that a longer ring finger indicates higher prenatal testosterone exposure, while a longer index finger suggests stronger prenatal estrogen influence.
The 2D:4D ratio is calculated by dividing the length of the index finger by the length of the ring finger. A lower ratio is associated with higher prenatal testosterone and more traditionally masculine traits.
What Did the Researchers Report?
They found the association between higher alcohol consumption and a low 2D:4D ratio was strongest in men whose right ring fingers were relatively long.
The exact reason for the link remains unclear. Manning suggests that higher testosterone levels could reduce alcohol absorption into the bloodstream, increasing tolerance.
“Enzymes in men’s stomachs can reduce alcohol absorption into the bloodstream by about 30 percent, while women generally absorb more alcohol,” the lead researcher said.
The team acknowledged the sample was limited to students, which may not reflect broader drinking patterns.
The findings were published in the American Journal of Human Biology.
What Else Do Scientists Know About This Strange Correlation?
Previous Swansea University research found children of higher-income mothers tended to have longer ring fingers.
Manning suggested that higher-income mothers might have relatively higher testosterone early in pregnancy, which could “masculinize” their children, while lower-income mothers might have lower testosterone levels leading to the opposite effect.
A 2021 University of Vienna study found that women with longer ring fingers than index fingers—an indicator of higher prenatal testosterone—tend to have stronger grip strength.
Another Scandinavian study found that when hungry, people with longer ring fingers than index fingers were more likely to choose stereotypically masculine foods, preferring steak over salad.
