A British scientist may have fathered up to 600 children at a controversial London fertility clinic which he set up in the 1940s with his wife.
The claim has been made by two men - a London-based barrister and a documentary maker - conceived at the clinic and who discovered they were his biological sons, the Daily Mail reported.
Documentary maker Barry Stevens from Canada and London-based barrister David Gollancz tracked down 18 other people conceived at the clinic. They found that 12, two thirds of those tested, had also been fathered by Bertold Wiesner, the scientist.
Wiesner is believed to have been one of the primary donors for the Barton Clinic, which helped women conceive around 1,500 babies, between the early 1940s and the mid-1960s.
From the results, Stevens and Gollancz argue that Wiesner, who died in 1972, must have fathered as many as 600 children.
Gollancz told the Sunday Times: "A conservative estimate is that he would have been making 20 donations a year.
"Using standard figures for the number of live births which result, including allowances for twins and miscarriages, I estimate that he is responsible for between 300 and 600 children."
Stevens believes the figure could even be as high as 1,000 as the clinic was known to use only a small number of intelligent donors selected out of Wiesner and his wife Mary Barton's friends.