Artificial organ almost always preceded by extensive experiments with animals. Initial testing in humans is frequently limited to those either already facing death or who have exhausted every other treatment possibility. Artificial arms and legs, or prosthetics, are intended to restore a degree of normal function to amputees. Mechanical devices that allow amputees to walk again or continue to use two hands have probably been in use since ancient times, the most notable one being the simple peg leg. Since then, the development of artificial limbs has progressed rapidly. New plastics and other materials, such as carbon fiber have allowed artificial limbs
Theology of the Body part of longstanding Church tradition — a tradition that was created in the context of scriptural teachings. The ability of the human body to express "truth" through the sexual union of married couples is acclaimed. The moral wrongness of using artificial means to manipulate such a significant aspect of the created body is explained. Dominion over outside forces, and also self-mastery through discipline, are integral human drives. However, the language expressed by bodies, in this context the language expressed during sexual intercourse, is so damaged by the use of artificial contraception that the conjugal act ""ceases to be an act