You're more unique than you know – Move over fingerprints. From your ears to your toes, many of your body parts make you uniquely special. And all of them are being investigated as a way to identify you from others in a crowd.
Every iris is unique – The pattern of your iris differs in each eye. This even holds true for identical twins. How does that happen? As the developing fetus opens and shuts its eyes in utero, iris tissue tightens and folds randomly, so no two can be the same.
It's all about touch – No one else has your exact fingerprints, even your identical twin. How can that be? It's all about the random way you used your fingers while the tips were developing in the womb. The density of your mom's amniotic fluid, how much you move, and your position in the womb are all thought to affect how those unique ridges formed on your fingers.
DNA is still the gold standard – Think of your DNA as four Legos that like to play in pairs along a spiral staircase called a double helix. Those pairs (A and T; C and G) form building blocks of code called genes that become the blueprint for your hair, eyes, body shape and everything else that makes you unique. There are almost 20,000 human genes, created from about 3 billion bases, so it's easy to see why no other human will have the exact same pattern of DNA.