Your fingerprints are uniquely yours. No one else on Earth - out of 8 billion people - has the same set of swirls and ridges on their fingertips. Even identical twins, who share the exact same DNA, have different fingerprints from each other.
Why? Because while DNA gives the general blueprint for fingerprints, the exact patterns are shaped by tiny random factors while you’re still in the womb. As your skin develops around month 5 of pregnancy, small variations in how cells push against each other, the position of the fetus, blood flow, and tiny chance events lock in the unique ridges you’ll have for life.
Once formed, your fingerprints don’t change. They grow in size as you get older, but the pattern stays the same. Even if your skin is damaged superficially, the prints regrow exactly the way they were. Only deep injuries that damage the underlying skin layer (the dermis) can permanently alter them. That’s why fingerprints have been used to identify people for over a century - and why it works so reliably.
