In the USA is is the law. Medical issues are private matters between a healthcare provider and patient. If a person's private information was to "get out" it might affect their ability to get a job or they might face other predjudices Also the private insurance numbers could be used to steal someone's identity.
Explanation: -CH_2OCH_3 has the highest priority according to the Cahn-Ingold-Prelog system used in assigning E and Z configurations of carbon-carbon double bonds
