British scientist fathered 600 children?

A British scientist may have fathered a record 600 children at a controversial fertility clinic here which he ran in the 1940s with his wife, a media report claimed today.

Bertold Wiesner, a biologist, and his wife Mary Barton, a doctor, founded a controversial fertility clinic in London that helped women to conceive about 1,500 babies.

Now two men who have discovered that they are Wiesner's biological sons have also found evidence that they say suggests he fathered hundreds of other children, The Sunday Times reported.

Barry Stevens, a documentary film-maker from Canada, and David Gollancz, a London-based barrister, were conceived by artificial insemination at the Barton clinic, as it was known.

Gollancz's research shows that Wiesner was regularly donating sperm to his wife's clinic from the early 1940s until the mid-1960s.

There has long been controversy about the clinic, set up in the 1940s, because it was believed to have used a small number of highly intelligent donors drawn from friends of Wiesner and his wife.

Derek Richter, a neuro-chemist, was reported to have fathered more than 100 of its children.

On the basis of DNA tests, Stevens and Gollancz now believe that the Austrian-born Wiesner himself made up to two -thirds of the total sperm donations.

DNA tests were carried out in 2007 on 18 people who had been conceived at the clinic between 1943 and 1962.

The tests showed that 12 of the group — two-thirds — were Wiesner's children.

Extrapolating from this, Stevens and Gollancz believe that his offspring must run at up to 600 children, the report said.

"A conservative estimate is that he would have been making 20 donations a year," Gollancz said.

"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."

Allan Pacey, an expert in male fertility at Sheffield University and chairman of the British Fertility Society, said Gollancz's calculation was "plausible."

Stevens believes the number of Wiesner's children could be as high as 1,000. But even 600 would dwarf previous records. Last year it emerged that one anonymous American sperm donor had fathered 150 children, the report said.

Wiesner died in 1972. Barton, who is also dead, always insisted she had limited the number of donations that could be made by any one man.