How is this different from a store just not stocking something or offering a service? You can't force someone to offer a service they don't want to. The doctor can simply say 'I don't offer that'.

So you go to somebody who does. If enough people don't go to a doctor because he doesn't offer a service he'll take a financial hit while his competition flourishes. For a doctor not to do offer something is no different than a store not carrying a certain product for what ever reason.

Doctors already refuse to do certain procedures for insurance reasons, or cost reasons, why is letting them refuse for another reason, yes religion, any different?