I have a friend who, after several years of dialysis, was told that her best chance for health and more years of life was a transplant. Two adult children were prospective donors. The daughter stepped forward, since she was childless after 10 years of marriage, and said “Why should my brother travel a long distance and leave his family to donate, this is my chance to give.” The transplant went well, the recipient felt better immediately, and the donor’s recovery was a little slower. (she did, after all, undergo some serious surgery.)
You can guess the punch line – a year later, the donor gave birth to a healthy baby boy. I’m not suggesting that the results are always this good, but it is a tremendous gift. It is entirely a personal decision, and if you decide to go ahead, it should be a brocha for you and your family.