Every patient has the right and capacity to decide on accepting medical treatment, even if a refusal might risk permanent injury to his/her health or even lead to premature death, and regardless of whether the reasons for the refusal were rational or irrational, unknown or even non-existent, if a patient’s capacity to make a decision had been overborne by the undue influence of others, it is the duty of the doctors to treat her/him in whatever way they considered, in the exercise of their clinical judgement, to be in his best interests. The dangerous practice of denial of therapy for various religious reasons affects almost all religious sects and, to a small extent, other religious groups. Jehovah’s Witnesses believe that accepting foreign blood blocks the way to salvation. They only agree to provide a medical service with the use of non-blood products. Therefore, treatment of such a patient can be extremely difficult for doctors. In other words, the arise is whether the rights of a mother refusing to have treatment can prevail against those of her unborn child, whereas potential limit to the absolute right of a competent adult to accept or reject treatment was recognized by English and American courts.