A recent study has found it's becoming more common for people to inherit two copies of chromosomes from one parent. Before having two copies of chromosomes from one parent resulted in disease. But now researchers are finding many healthy individuals have this trait. They found that uni-parental disony (UPD) occurs in one out of two-thousand. It is twice as common as once believed. UPD can affect any chromosome, including sex chromosomes. Researchers compared homozygostity between pairs of chromosomes. They found having two or more chromosomes from one parent was linked with smaller body weight. Having two copies of chromosome twenty-two gave people a higher risk of autism. Other than that UPD doesn't result in many harmful risk factors. While in the past UPD caused lots of health issues in people who carried UPD. Now after this study it was found that more healthy people have UPD.