BUT - they all have one thing in common that makes them different. DNA is often called the building block of life. DNA is a long string of chemicals, and it's like an instruction book for your body, or a plan, so the cells in your body use the DNA so they know what to do, and what you should look like, and how to make your body work. In fact, there's about two metres of DNA, coiled really really tightly, in every cell. Sonya Dechian, Science Graduate DNA is what determines individual characteristics like the colour of your eyes, skin, hair - and lots of other stuff too.
Scientists call it a genetic fingerprint.
DNA might just look like squiggly rubbish. But to a scientist, DNA is like a bar code. The only people that do have the same DNA are identical twins. They look the same, and their DNA is the same. Everyone else's is unique.