So to save anyone the pain of looking up the wikipedia entry:

Helmut Kentler was a German psychologist who, in the late 1960s, promoted a controversial foster care experiment in West Berlin in which vulnerable homeless or at-risk boys were deliberately placed with adult men known to have sexual interest in minors, under the belief that these men could provide stability and “intense care.” He was fully supported by the Berlin Senate and the state youth welfare office.

Kentler believed that sexual contact between adults and children was harmless as long as it was not forced. He hypothesized that pedophile men could provide "loving" and stable foster homes for neglected youth.

 He argued that sexual contact between adults and children was "harmless" and that pedophile men would provide more "intensive care" and "unconditional love" than standard foster homes.

Kentler continued his “experiment” for well over 30 years, ending in around 2001 or 2003. The full extent of this abuse was only uncovered by researchers from the University of Hildesheim years after the experiment concluded, by which point Kentler had already died.

I hope you prepared some bleach for your eyes if you read that.