Question: Can DNA help scientists predict what might happen to someone's future, medically?

Brian Zhang answered on 14 Nov 2019:

If you think about things not as black-and-white, but in terms of odds / probabilities, then I think yes. Nothing is determined and can be predicted perfectly in this world, there’s always an element of chance. So I can’t tell for sure even if I had a person’s DNA would diseases they would get, as we know there’s a lot of environmental factors at play. But maybe most people have a 5% chance of getting a disease before age 50, whereas from someone’s DNA I can predict that they have a 50% chance, and have that prediction be mostly correct. (For all the people I predict at 50%, about half of them end up going on to have the disease.)

However, the real power of using DNA is not so people feel like this is their medical fate, but so they can have tips how to reduce their risk, like exercise, eating certain foods, or taking medicines.