I know people may not like this idea, but shouldn't we just use rapists and paedo's for medical experiments?
The very nature of their offences is addictive, so if they offend, say, 3 times, it's reasonable to assume that they did it (framed 3 times?! 3 false positives?!) and will do again; ruining other peoples lives and increasing the possibility that these people will go on to ruins yet more peoples lives (paedophiles victims are, bizzarrely, more likely to become paedophiles).
So why not use them for medical experiments? Stops them re-offending, more accurate than using ******* and because they would become government property once convicted a government could make a lot of money from them to support victims of ****, for example.
Alternately, use them to help cure cancer/aids. What better testbed for a cure in humans than....a human?
Lets not forget that by sacrificing their victims human rights they have themselves made a statement that a humans rights can be sacrificed...