Also Read | Viagra May Reduce Cancer Metastasis, Study Shows; Here’s How and Why. 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. It's not easy to say why, on a biological level, younger generations are aging faster than their parents and grandparents. Determining an individual's biological age is the "subject of current scientific research, but in no way a practical routine or part of everyday clinical work."