The German Cancer Research Center (DKFZ) has reported a sharp increase in gastrointestinal cancer cases for patients between the ages of 20 and 39. The reason, they suggest, is that younger generations are displaying a wider gap between their biological and their chronological ages. DNA, bloodmarkers and telomeres: How to determine one's biological ageIt's not easy to determine a person's biological age. We used to assume that a healthy lifestyle could make up 75% to 90% of one's biological age. It's not easy to say why, on a biological level, younger generations are aging faster than their parents and grandparents.