Accurate Age Guessing From Blood, Saliva and Semen

Scientists have found a way to estimate how old someone is by looking at tiny chemical changes in three different body fluids. They started by picking out three spots on DNA that change with age, using data from public studies. Then they measured how much those spots were altered in the blood of 101 healthy people with a technique called pyrosequencing. Using these measurements, they fed the data into computer programs that learn patterns and built several age‑prediction tools. The simplest model, a straight‑line equation, gave the best results: it could guess age within about 3 years for blood, 3.5 years for saliva and a little over 4 years for semen. Even when only tiny amounts of DNA were available, the method still worked well. However, if certain chemicals like oxidized heme or humic acid are present in high amounts, the test stops being reliable. Overall, this new approach lets investigators estimate a person’s age from any of the three fluids without first having to figure out which fluid it is, saving time and sample material at crime scenes. The technique could make forensic investigations faster and more dependable.