Kurt Freund

Kurt Freund devised his famous erection-detection machine after being approached by the Czech army, who were concerned that straight recruits were claiming to be gay to avoid military service. Freund set about creating a machine to monitor the recruits’ erection, or lack thereof, when presented with images of naked women. Whether a man became aroused or not would reveal his true sexuality.

While the machine has been refined over the years it still functions in much the same way Freund intended. A man sits into a chair featuring an erection gauge that connects to his penis. This gauge can detect subtle changes in the rigidity of the man’s penis. As he is shown images of nude models, both male and female, adult and youth, a scientist monitors his reaction to the stimuli.

Freund could not have imagined how his device would be repurposed in the future. Today, it’s most commonly used in the legal system to determine whether men charged with crimes against children are pedophiles.

Freund himself acknowledged that his invention had limitations, and its usage is controversial today. For example, it’s believed that sex offenders could suppress their arousal by concentrating on something else or inflicting pain on themselves. Yet Freund believed that it was difficult for men to consistently suppress their sexual response, and they could not fake it. Because of this, Freund maintained that his invention was the best way to measure male sexual response. Freund also determined that men were either straight or gay, as he believed he had not seen evidence of bisexuality in men.