Are Ova Donors Encouraging Incest?

During the process of selling some genetic material, I found myself tapping into a social anxiety I couldn't quite understand. A few people around me--including one ultrasound technician--were worried that two of my spawn, born to different mothers through anonymous donations, would meet and fall hopelessly in love. Not knowing that they were genetically related, they would go on to reproduce. I thought this, um, statistically improbable. But for at least one member of the House of Lords, this possibility is enough to require all mothers who use donated sperm to disclose that fact:

A couple discovered after they had married that they were twins who had been split up at birth and adopted by separate families, according to a member of Britain's House of Lords.

British peer David Alton recounted the story to parliament last month to support his argument that artificially conceived children should be told who their biological parents are…

Alton said he had heard the story of the separated twins from a High Court judge who had dealt with the case.

"They met later in life and felt an inevitable attraction, and the judge had to deal with the consequences of the marriage that they entered into and all the issues of their separation," he said.

"I suspect that it will be a matter of litigation in the future if we do not make information of this kind available to children who have been donor-conceived," he said.

Note that this situation did not involve sperm or egg donation. And, given the lack of names here, the argument amounts to: "My judge friend told me about this thing that happened one time." I guess that's enough to make a new law in Britain at this point. 

Hat Tip: Bill Piper.