What is it to be healthy?

According to Christopher Boorse's Bio-Statistical Theory (BST), 'health' is statistically normal function in a reference class, and 'health' and 'disease' are empirical, objective and value-free concepts.I demonstrate that the success of the BST depends on its choice of reference classes; different reference classes result in different accounts of health.I argue that nothing in nature empirically or objectively dictates the use of reference classes Boorse proposes.Reference classes in the BST, and the concept of health, are therefore not value-free.Nor is there a reason to favour the BST over accounts of health that use different reference classes.