Here in Canada, GP's don't do abortions, ob-gyn's do. I don't think any doctor should be required to do abortions against their conscience, unless it's an emergency situation. In that case, the only doctor I could see being put in that situation would be an ob-gyn on-call at a hospital. If I go to my GP for a referral to an ob-gyn for an abortion, and she refused to do the referral, she should refer me to a GP that will do it.
Darkmoon, veterinarians absolutely do (and should) have the right to refuse to do ear cropping, tail docking, declawing etc. I have heard of vets who refuse to do some or all of those procedures. They can refuse to do any procedure they choose to not do.