I feel like it could be useful in making people less likely to get cancers, allergies and the like but then where would you draw the line?
People have different views of what are problems and in some cases people view mental conditions as negative but they are also what makes a person who they are (I'm trying not to cause an argument with this).
In summary things that are only negative like the aforementioned autoimmune diseases, cancers and allergies should be prevented as they do not make up the person's personality they are just a predisposition to illness and the person would live better life without them.