But now scientists have documented that fact on a genetic level. Researchers discovered that normal, healthy people are walking around with a surprisingly large number of mutations in their genes. It's been well known that everyone has flaws in their DNA, though, for the most part, the defects are harmless.

What percentage of people have mutated genes?

After all, a population riven with genetic mistakes would quickly die out, or so went the logic. However, the present study puts the fraction of people with mutations linked to genetic diseases at something closer to 20 percent.

How common is a gene mutation?

One in five 'healthy' adults may carry disease-related genetic mutations.