How did I get my own unique set of fingerprints?
contributed AP

How did I get my own unique set of fingerprints?

(The Conversation is an independent and nonprofit source of news, analysis and commentary from academic experts.)

Sarah Leupen, University of Maryland, Baltimore County


Curious Kids is a series for children of all ages. If you have a question you’d like an expert to answer, send it to

How do we get the fingerprints we have? – Oscar V., age 8, Somerville, Massachusetts

Fingerprints are those little ridges on the tips of your fingers. They’re essentially folds of the outer layer of skin, the epidermis. The “prints” themselves are the patterns of skin oils or dirt these ridges leave behind on a surface you’ve touched.

Your fingerprints began to form before you were born. When a fetus starts to grow, the outside layer of its skin is smooth. But after about 10 weeks, a deeper layer of skin, called the basal layer, starts growing faster than the layers above it, which makes it “buckle” and fold. The expanding lower layer ends up scrunched and bunched beneath the outside layer.

These folds eventually cause the surface layers of the skin to fold too, and by the time a fetus is 17 weeks old – about halfway through a pregnancy – its fingerprints are set.

Although this folding process might sound random, the overall size and shape of fingerprints are influenced by the genes you get from your parents. So you probably share some fingerprint patterns with your family members.

But the details of your fingerprints are influenced by many other factors besides genes. For example, the shape and size of the blood vessels in your skin, how fast the different layers of skin are growing, and the chemical environment inside the womb all play a part. No two people end up with exactly the same fingerprints, even identical twins.

It was only in 2015 that a big long-term study showed that fingerprints are stable over a person’s lifetime. The ridges of a fingerprint are visible on the skin’s surface layer, but the pattern is actually “encoded” below that. Even if you have a major skin injury, your prints will come back when the outer layer heals – though you might have a scar, too.

So your fingerprints are totally unique to you and have been since before you were born. No matter how much you change as you grow up, you’ll always have the set you have now, no matter how long you live.

What’s a fingerprint’s point?

Surprisingly, nobody really knows what fingerprints are for.

People have long thought that fingerprints provide the friction that helps our hands grip objects. This makes sense because the other animals besides human beings that have fingerprints – including many other primates like apes and monkeys, and koalas – are all tree climbers.

But sometimes what makes sense isn’t true, and a recent study found that fingerprints don’t really help people hold onto things – at least, not things with smooth surfaces.

Other possibilities are that fingerprints improve your sense of touch or help protect your fingers from injury. But scientists don’t know for sure yet.

Making use of your prints

Police have been using fingerprints and their unique loop, whorl and arch shapes to help catch criminals for more than 2,000 years, starting in ancient China.

Fingerprints are now used for many other things as well, all based on the fact that each person’s fingerprints are different. You can use that unique code to unlock your phone or enter a restricted area, for example. In Malawi, fingerprints have been used to identify farmers who have taken out loans. They can even be taken from babies and used throughout the person’s life to access their immunization records.

Police forces are still finding new uses for fingerprints, too. As fingerprint detection and study methods have improved, detectives can even use them to see who threw a particular stone. Those little ridges can hide tiny amounts of substances too – which means they could be used to detect the use of illegal drugs like cocaine and heroin. And now forensic scientists can detect decades-old fingerprints, too – maybe allowing detectives to solve really old crimes – with a new technique that uses a color-changing chemical to map the sweat glands within your fingerprints.

Hello, curious kids! Do you have a question you’d like an expert to answer? Ask an adult to send your question to Please tell us your name, age and the city where you live.

And since curiosity has no age limit – adults, let us know what you’re wondering, too. We won’t be able to answer every question, but we will do our best.

This article is republished from The Conversation under a Creative Commons license. Read the original article here:

The Conversation

This content was contributed by a user of the site. If you believe this content may be in violation of the terms of use, you may report it.

Related to this story

Most Popular

Do you think it is permissible to yell "fire" in a crowded movie theater in order to create a panic? How about whether it is legal to speak to a crowd and tell them to go out and shoot the first police officer they see, or homeless person or teacher? If you responded no to those questions, does that make you an opponent of the First Amendment and its ban on laws that abridge the freedom of ...

The Alzheimer's disease tsunami is coming our way, and it is being propelled by the demographics of the baby boomers - the oldest of them turned 75 in 2019. Today, there are nearly 6 million Americans with the disease, according to the Alzheimer's Association, a number expected to nearly triple by 2050. The significant increase in the number of people diagnosed with Alzheimer's will be a ...

Medicaid, Medicare and Social Security are among the most popular federal programs out there. A 2019 Pew Research poll showed majorities across all parties and demographics opposing cuts to Social Security. A Public Policy Polling survey that same year found broad opposition to slashing Medicaid or Medicare. The programs are so popular that Donald Trump himself, back in his 2016 campaign, ...

Picture a cool running stream - a ribbon of life in southern Arizona's rocky deserts. Now envision bulldozers stripping the surrounding land and erecting steel slats right across it. President Donald Trump wants to build part of his promised border wall on top of one of the last free-flowing rivers in the American Southwest. In late January, more than a thousand people gathered at an event ...

  • Updated

We have stepped through the looking glass, or entered George Orwell's dystopia. Criminals are victims. Public servants are criminals. Truth is a lie, and lies told loudly and persistently carry the day. We are at a tipping point where the bedrocks of our society are under attack. President Donald Trump commuted Rod Blagojevich's sentence Tuesday. Blagojevich will loudly proclaim his innocence, ...

If a policymaker proposed banning cars and trucks or reducing the speed limit to 5 mph to reduce traffic fatalities, he or she would be laughed off the stage. Such a policy ignores the benefits of driving and disregards how people accept risk and tradeoffs in their lives. So why should we treat efforts to ban fracking any different? Hydraulic fracturing, better known as fracking, is safe. ...

Michael Bloomberg is coming under fire for many things, including his role in overseeing the New York City Police Department at the height of its stopping, questioning and frisking young black and brown men. There's a distorted story being told. I want to explain what I saw up close. I personally witnessed Mayor Bloomberg's determined attempt to come up with an alternative to stop and frisk at ...

All of the Democratic candidates for president are well qualified, and all of them could potentially defeat President Donald Trump, but not one of them has made a genuine effort to unite some core ideas of moderates and conservatives with progressive ideas. For all of the talk about the centrists vs. the progressives - Joe Biden, Amy Klobuchar, Pete Buttigieg and Michael Bloomberg vs. Bernie ...

On Feb. 8, the night before I went to a vigil for Dr. Li Wenliang in New York's Central Park, one of my friends warned me: "Wear a mask and sunglasses. Don't show your face. Protect yourself." I thanked her for her kindness but decided not to wear any "protection." What danger would I face if I'm just mourning a doctor who had saved countless lives by being a "whistleblower" about the rapidly ...

Some Democrats complain about billionaire former New York City Mayor Michael Bloomberg trying to buy the election, but at least he's doing it with his own money. President Trump is using yours. Let's break down that Friday morning tweet. Farmers are being "formally targeted" by foreign countries because Trump picked a trade war with the entire globe, first with tariffs on solar panels, then ...

Get up-to-the-minute news sent straight to your device.


News Alerts

Breaking News