HEALTH CARE DIRECTIVES   Modern medical science has made advancements in life-sustaining medical treatments.     These procedures have raised new ethical and legal questions about a patient’s wishes to receive such treatment during terminal illness or incapacity.  To answer the question, "What sort of treatment would the patient want if competent?" the legal community has created new documents collectively referred to under the umbrella term "advance medical directives."     Advance medical directives include living wills, health care powers of attorneys, and medical directives, and sometimes instructions about organ donations.     What Is a Living Will?     A living will is a document that allows people to specify the life-sustaining treatments they would find acceptable in the final days of terminal illness or incapacity. Forty-seven states and the District of Columbia have living-will laws (all states except Massachusetts, Michigan, and New York).     This statutory right has arisen because modern medicine can keep people alive beyond any reasonable expectation of recovery.     Courts have struggled with determining who has the right to make decisions which will maintain the dignity and respect the wishes of dying patients.     These two equally powerful forces have produced a shift in public opinion on death and dying which has affected public policy.Today people are not only concerned with providing for the disposition of their property at death, they are also seeking to leave clear advance directives on their wishes as they relate to life-sustaining care while they're alive.     Background on Living Wills     Living will statutes have proliferated in an attempt to define an individual's right to forgo life-sustaining treatment.     The United States Supreme Court clarified this matter in its l990 decision, Cruzan v. Director, Missouri Department of Health. While the Court recognized the right of a competent person to direct that life support be removed, it upheld the state's right to require that clear and convincing evidence be shown as to the wishes of an incompetent person.     Absent proof, the Court found that the state was not required to assume the family's wishes were those of the comatose daughter.     Although the Supreme Court's position is clear, the case allows each of the 50 states to write its own rules, which has resulted in a patchwork of statutes that vary from state to state.     Generally, a competent person is permitted to instruct his or her physician to withhold or withdraw life-sustaining procedures in the event of a terminal illness.