For the first time researchers from Hebrew University of Jerusalem, Radboudumc, Maastricht UMC+ and international colleagues have gained insight into the “hidden genetic defects” of the general European population. This is important because these defects, if inherited from both father and mother, can lead to all kinds of illnesses in their children. Research in the Dutch and Estonian population shows that every person has two to four such hidden genetic defects. In 1 in 100 couples, this leads to a situation with an increased risk of a genetic disease for future children. In the case of consanguinity, even 20 percent of the couples appear to be at high risk. This research is published in The American Journal of Human Genetics and Genetics in Medicine.