CONCUR...
Any doctor would be within his or her rights to refuse to perform any purely elective, medical procedure on any particular patient. The doctors refusal requires no justification beyond his or her professional and personal judgment. A patient disagreeing with such a judgment is free to find another doctor who may not be so disinclined.
DISAGREE...The doctor may be within his rights legally but morally and ethically he is supposed to provide the medical care to alleviate his patient's affliction (in this case her inability to conceive children). After all, he's not being asked to perform an abortion (in which case I would agree with you) he is only being asked to provide the patient with treatment to enhance her fertility--which is the same request many hetrosexual women ask of physicians.
Disingenuous. He is being asked to artificially inseminate her... make a new life inside her artificially. He already provided fertility treatment. If she is now fertile, she can handle the rest on her own initiative...