UCLA professor Steve Horvath has figured out a new way to measure the age of your organs—the DNA Methylation Age Calculator.

How does it work? Turns out our DNA has 353 markers which change as we age. Typically this change is uniform across the human body. But not always. Which means we can now measure organs’ ages in relation to one another. For example, cancer tissue is on average 36 years older than healthy tissue from the same body. Also, women’s breast tissue ages faster than their other tissue, which may explain why breast cancer is so common among women.

In healthy tissue, our organs’ Methylation Clock runs fastest while our bodies are still developing up until age 20. Then after 20, the process “slows down to a constant ticking rate” and remains that way until we die.

This discovery may not seem like a big deal, but the more we know about the aging process the better we’ll be at slowing it down. Horvath isn’t promising a cure to aging, but he admits that in theory it’s possible. In 2012, scientists Sir John Gurdon and Shinya Yamanaka were awarded the Nobel Prize for figuring out how to turn adult cells into stem cells. Essentially, this process turns the cell’s Methylation Age back to zero. According to Horvath, this “provides a proof of concept that one can reset the clock.”