According to the BC Supreme Court, yes.
VANCOUVER - The B.C. Supreme Court on Monday upheld an earlier court order authorizing a blood transfusion for a 14-year-old cancer patient who doesn't want the procedure because she's a Jehovah's Witness.Part of me wants to say "This is what you get for trying to give the Watchtower!" but I'm actually rather puzzled by this story. At my most theological, I've never felt a religious belief would get in the way of a necessary medical procedure for me or a loved one. That said, I can't say I love the idea of the guvmint getting in to someone's life like this. I suppose, if I suported Terry Schiavo's right to choose her fate, I should support this girl's decision out of consistency if nothing else.
Though she has consented to chemotherapy, surgery and the possible amputation of her leg, the teen says a transfusion violates her religious beliefs.
Can't say I have anything to add. Just saw this come across my RSS reader, thought I'd share.
(By the way, some of us will remember that Babylon 5 did an episode dealing with much the same issue. The kid ended up surviving the operation, but his religious parents killed him afterwards.)