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.
Even identical twins have different DNA – Breakthrough studies in the last year show even identical twins have different DNA. Using second generation genome sequencing, says Bowyer, "If you do a more detailed and deeper level construction of DNA, you find that once that fertilized egg splits there are random mutations that are happening and that can be used to identify differences between twins."
Your 'eau de parfum' – The Pentagon is hard at work trying to analyze your personal smell, the one that's linked to your genetics. It's believed dogs recognize their owners in that manner, and the military is trying to wade through the more than 300 compounds that can produce a human's smell.
The window into your health – The pattern of blood vessels displayed on the retina at the back of your eye is a very precise snapshot of your nervous system — unique to you. Ophthalmologists can see telltale first signs of diabetes, multiple sclerosis, high blood pressure, even brain health. Smart phones are taking the technology to Third World countries.
Nothing stays the same – Even our unique bits change as we age, which makes it challenging for those who want to identify us.
"Is there anything that never changes at all? I wouldn't say that," says Bower. "But for things we think are pretty stable, or we know how they age, generally we have some sort of idea through aging recognition techniques."