You may have just celebrated your 30th, 50th, or 75th birthday, but the cells that make up your body are actually much younger than that. If you go by the numbers, your cells are, on average, around 10 years old, or less.
In fact, most of your body’s cells are constantly being replaced, although its DNA stays the same from the moment the cell is first created (by its parent cell dividing).
Because of this, Jonas Frisen, a stem cell biologist at the Karolinska Institute in Stockholm, was able to develop a method to determine just how old your cells really are.