I understand and respect both sides of the argument, but if I could share my own experience and change just one persons perspective on this, that would make me very happy.
I have been in the fortunate position to be able to donate a kidney to my beautiful younger Sis. That was 5 years ago. Nothing changed for me, I have one kidney that is doing a grand job and my Sis has her life back to some sort of normality, doing all the things we take for granted.
Sadly I know of two others (one a family member and one a friend of the family) currently undergoing dialysis - if I could return to the wonderful renal unit at the Northern General tomorrow and donate again I would do so in a heartbeat.