CQ u say don't mix religion with medicine. That is impossible. No matter what a doctor is a person with his/her own morals and beliefs. Should he/her give up all their beliefs for their patient's wishes ?

Also, the grounds are not only religious. Here are a few arguments:

1. The dedication of the medical profession to the welfare of patients and to the promotion of health might be seriously undermined in the eyes of the public and of patients by the complicity of physicians in the death of the very ill, even of those who request it. It is possible that subtle changes would enter into the relationship of patients and their physicians should such a practice become common.

2.Requests for swift death often are made in circumstances of extreme distress, which may be alleviated by skillful pain management and other positive interventions such as those used in hospice care.

3. Even if initial toleration of euthanasia is limited to the voluntary situation, it is possible that, once established, the practice might become more acceptable for involuntary patients whom others assume "would have requested it" if they had been able.

The "euthanasia" program initiated in Germany in the first half of the last century with the support of many benevolent physicians was first directed only to the incurably ill; it gradually expanded into genocide

(This was taken from a book called Clinical Ethics)