In the United States, people may donate organs and tissues to a family member, friend, or anyone whose specific need becomes known to them. For example, in late 2003 dozens of people came forward to donate a kidney to a professional basketball player known to them only through his sports performances. People may also donate a kidney to no one in particular through a process known as nondirected donation. In nondirected donation, people donate a kidney to the organ allocation system rather than to anyone known to them personally. There are limits, though, to generosity. People are usually not allowed to donate to groups of people, no matter the contours of the group, whether white, black, Catholic or Presbyterian, third-time liver recipient, and so on. As the agency that oversees national transplantation policy, the United Network for Organs Sharing (UNOS) does not allow this sort of restricted donation, though it appears that some regional Organ Procurement Organizations (OPOs) occasionally bend the rules when donors insist that their organs go to children or to first-time recipients. Those ad hoc arrangements are, however, the exception to the rule.