Say What?! Fingerprints, A Crazy Concept - Allbodies

Say What?! Fingerprints, A Crazy Concept

Say What?! Fingerprints, A Crazy Concept

Say What?! Fingerprints, A Crazy Concept

Have you ever stopped to think about how your fingerprints are formed? After all, they are truly unique to each and every single person in the entire world (!!!) Even identical siblings (more on this later), have their own set of custom-made fingerprints. They’re bespoke digital tips, if you fancy. So yes, dear, you really are a special snowflake.


Fingerprints are formed during a fetus’s time in utero. No exact time frame has been pinpointed, but formation seems to be complete by between 17-26 weeks gestation*. So beware; Your fetus could be identified by fingerprint for any crimes committed in utero! #dadjoke

*Editor’s note: every source had a slightly different timeline!


There are multiple factors to how fingerprints are formed.


As the fetus begins opening its hands, splaying its fingers and exploring its environment, the skin on those tips is brand spankin’ new and quite impressionable—like a just opened jar of smooth peanut butter! In addition to how the skin layers buckle and fold in development, the pressure of the amniotic fluid against those fingertips and the movement they make are thought, in part, to create the ridges that make up the fingerprint.(1) #noway!

There are three basic patterns of fingerprints: whorl, loop, and arch.



Some people have one type, others two, and others all three types. There’s a genetic component, in that some people are more predisposed to having the same pattern as their parents, e.g: all loops except for the left thumb. That being said, it’s not the pattern that makes a fingerprint unique—it’s the specific angle of the arch, the rise of the whorl, the crest of the ridge, etc. That’s where the fetal development plays a role. So while mom and dad may pass down arches in their DNA, it’s the fetal movement inside the womb that makes baby’s arches uniquely theirs.


According to Scientific America, the technical term for the skin that develops as the fingerprints are formed is called friction ridge skin. FRS helps humans grip things. Imagine how hard it would be to turn the pages of a book wearing silk gloves—that’s what FRS helps us do! #whoknew?!


Even the most identical of twins (or any other multiple siblings, identical or not) don’t do exactly the same thing in utero. They move around differently, touch different parts of the womb walls, and spread their fingers in different ways. Which means different fingerprints.

HOLY SHITBALLS are fingerprints COOL.

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Written By: Kristin Freeman, Certified Sexuality Educator from OH

+ References

(1) “Where Do Fingerprints Come From?”, Smithsonian Institution,

(1) “Where Do Fingerprints Come From?”, Smithsonian Institution,