Bertold Wiesner, biologist, fathered hundreds at own fertility clinic

Who's your daddy?

If you were conceived with the aid of a sperm donor, your father might just be Bertold Wiesner. The Austrian biologist who opened a fertility clinic in London, England with his wife in the 1940s has helped approximately 1500 women to conceive, reports the Telegraph.

But Wiesner may have had more of a hand in these pregnancies than anyone realized at the time.

Check out a video news report here:

Although the sperm donors from the clinic were taken from a small pool of highly intelligent candidates, the pool may have been smaller than reasonably expected. DNA tests on 18 people conceived at the clinic between 1943 and 1962 showed that Wiesner himself was the biological father of two thirds of them.

"A conservative estimate is that it would have made twenty grants per year," David Gollancz, one of the many children conceived at Wiesner's fertility clinic who was fathered by Wiesner, tells the Sunday Times. "Using standard figures for the number of births that result, including twins and miscarriage, I think he is responsible for between 300 and 600 children."

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Since Wiesner's time, laws have been put into place in the U.K. prohibiting men from making bulk sperm bank donations in order to minimize the risks of half-siblings unknowingly falling in love and subsequently procreating.

There is currently no limit to the number of offspring that sperm donors in Canada or the United States can produce, reports the Toronto Star.

One American sperm donor, Kirk Maxey, estimates that he's the father of anywhere between 200 to 400 children.

Check out the video below about children being made fun of because they have two fathers.