A Toronto doctor launched a smartphone app to predict the size of men's penises.

Predicktor uses "only physical attributes proven by scientific research to be associated with penis length and discards all others, like race."

Those proven attributes include things like height and finger length, which have been linked to penis length by studies in the European Urology Journal and the Asian Journal of Andrology, respectively.

But the app doesn't just guess a trouser snake's measurements. It also debunks the notions that race or shoe size have anything to do with male genitalia, while assuring men that porn stars' ding dongs aren't the norm.

"The Predicktor is an entertaining antidote to the widespread insecurity, anxiety and dissatisfaction among men over their penis size," Dr. Christopher Culligan said.

Culligan is CEO of The Doctor Says, developer of the Alcohol Addiction Predictor and the Depression Predictor.

Predicktor is available on Android devices for $2.99. A BlackBerry version will be available next week.