A scientist in the UK, who founded a fertility clinic promising intelligent donors, might have fathered up to 600 children after donating hundreds of times at his own clinic.

Biologist Bertold Wiesner has reportedly donated sperm to the partners of infertile men belonging to the middle and upper classes. His wife, Mary Barton later destroyed records so hundreds of subsequent offspring have no way to trace their blood ties.

According to two men, who were conceived by artificial insemination at the clinic, about two-thirds of sperm donations from early 1940s until the mid-1960s were of Wiesner. They compiled the information in a research.

David Gollancz, one of Wiesner’s biological sons said that he would have made 20 donations a year. This indicates that he is likely to have fathered between 300 and 600 children. Gollancz discovered at the age of 12 that he was born from a sperm donor but did not know who his biological father was.

He came to know about Wiesner through DNA tests and then made contacts with 11 of his half-siblings, including documentary-maker Barry Stevens. Stevens led the research study into the clinic.

He said that it is uncomfortable for his as artificial insemination was developed on an industrial scale for breeding cattle and added that he did not like the feeling of being bred at a lab.

“But meeting the half siblings that I have tracked down has been a very life-enriching experience. This does make it frustrating too, because I know there are all those other siblings out there who I don’t know but would really like to meet. I’d love to be able to hire a huge marquee and invite them all to a party,” he said.