> if you want to get the kit and test your DNA out of fun, at least make sure your identity is not obvious.
Once a relative uses the service with their real identity, even if you don't use the service yourself, wouldn't the company know your family (and thus you) have a high chance for X disease or traits?
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%.
Once a relative uses the service with their real identity, even if you don't use the service yourself, wouldn't the company know your family (and thus you) have a high chance for X disease or traits?