(CNN) -- South African Dr. Sonnet Ehlers was on call one night four decades ago when a devastated rape victim walked in. Her eyes were lifeless; she was like a breathing corpse.
"She looked at me and said, 'If only I had teeth down there,'" recalled Ehlers, who was a 20-year-old medical researcher at the time. "I promised her I'd do something to help people like her one day."
Forty years later, Rape-aXe was born.
Ehlers is distributing the female condoms in the various South African cities where the World Cup soccer games are taking place.
Once it lodges, only a doctor can remove it -- a procedure Ehlers hopes will be done with authorities on standby to make an arrest.
"It hurts, he cannot pee and walk when it's on," she said. "If he tries to remove it, it will clasp even tighter... however, it doesn't break the skin, and there's no danger of fluid exposure."
Ehlers said she sold her house and car to launch the project, and she planned to distribute 30,000 free devices under supervision during the World Cup period.
"I consulted engineers, gynecologists and psychologists to help in the design and make sure it was safe," she said.
After the trial period, they'll be available for about $2 a piece. She hopes the women will report back to her.
"The ideal situation would be for a woman to wear this when she's going out on some kind of blind date ... or to an area she's not comfortable with," she said.
The mother of two daughters said she visited prisons and talked to convicted rapists to find out whether such a device would have made them rethink their actions.
Some said it would have, Ehlers said.
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