A controversial program rewards prison inmates who behave particularly well in prison by giving them the chance to receive free cosmetic plastic surgery performed by medical students  The program is obviously morally questionable, both in its assumptions about what inmates might want and in its use of the prison population to train future surgeons
Putting these moral issues aside, however, the surgery clearly has a powerful rehabilitative effect, as is shown by the fact that, among recipients of the surgery, the proportion who are convicted of new crimes committed after release is only half that for the prison population as a whole
allows moral issues to be a consideration in presenting evidence about matters of fact