Some serial lust killers suffer from erectile dysfunction in the context of a consensual relationship with a living human. In one sample of them, 44 per cent indicated erectile difficulties. It appears that some killers can only secure and maintain an erection, if at all, in the presence of a dead body, as with John Christie, or blood, as with Andrei Chikatilo. More speculatively, Robert Lee Yates Jr. also fits this description. It appears that John Christie was mocked for erectile difficulties. He viewed the body of his grandfather, which possibly had a role in the tragedy. It is possible that being gassed in World War I contributed to his pathological sexuality. Andrei Chikatilo is the most famous serial killer from the USSR. His early life in the Ukraine was associated with a multitude of different stressors. His erectile difficulties might have stemmed in part from bullying and taunting.