Yes, it has some effect on the human body and on the health in a whole. At first, it is always a risk, that the only one kidney can not normally work, and it sometimes may leed the person to groving in weight and many other possible problems. But having a special diet and special way of life may leed the person to the healthy existance. But from the other hand you may give the other person a chance to be alive, even with sme small problems with the health. The life is much more presious thing, so you may make the most presious present for another person.