To heck with them, their 'consent', and/or their rights.
or...maybe i should clarify.
I believe a certain 'segment' of the criminal population should be used to better our understanding/knowledge. Lets see...we could start with violent offenders (murder, repeated assault, rapists, etc.), pediphiles for sure...and..umm.. thats all i can think of at the moment.
Call me conservative or cold-hearted (i dont consider myself any of these)...but this is my opinion.
Of course the perpretrators of victimless crimes should be exempt...
I think the best argument 'against' my point of view is that this would place us on a slippery slope...and a potential quick slide to a nazi-type state...but i dont think so...so long as we limit the research to violent/sociopathic criminals who've blatantly demonstrated their own disregard for their 'fellow' human beings' rights. In which case i think they should be treated as though they've in turn given up their own 'rights'.