Short answer is yes, but it depends on the relationship and the disease. For example, if a parent takes the test and is positive for a breast cancer risk gene

Short answer is yes, but it depends on the relationship and the disease. For example, if a parent takes the test and is positive for a breast cancer risk genetic variant, then all offspring will have at least a 50% chance of the same result. If, instead of a parent, a grandparent is tested, that percentage drops to 25%.