Twins adopted by separate parents soon after birth later fell in love and married, unaware they were related, it emerged yesterday.
The couple, who have been granted anonymity, had their marriage annulled at a special High Court hearing, where judges ruled that the union had never been legally valid.
The case emerged during a debate in the House of Lords yesterday when the pro-life campaigner Lord Alton of Liverpool raised the couple's plight to highlight what he said were deficiencies in the Human Embryology and Tissues Bill, currently making its way through Parliament.
The couple, who were conceived normally, were adopted by different parents and separated soon after birth. They were never told they were twins and did not discover the truth until after their wedding.
Lord Alton, who learnt of the case from a High Court judge, is concerned the Bill, which makes it easier for lesbian and gay couples to have "test-tube" babies, weakens the rights of a child to know their father.
He said: "[The brother and sister] met later in life and felt an inevitable attraction, and the judge had to deal with the consequences of the marriage and all the issues of their separation.
"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."
The new legislation gives clear recognition to same-sex couples as legal parents of children conceived through the use of donated sperm, eggs or embryos.
But Lord Alton objected that there would be nothing on the child's birth certificate to let it know they had been donor-conceived, and raised particular concerns that IVF, where it was legally possible to father up to 10 children, would increase the likelihood of such cases re-occurring. The peer said yesterday that he was worried that the biological identity of one parent could be removed from the birth certificate and recommended that the genetic history of a child should be kept on record to prevent further mix-ups.
"The state is colluding in a deception," he said. "We are opening the door to more cases like this one. One of the most fundamental things of all is to know who you are. The issue here is about human rights. A birth certificate that omits any mention of your true origin falsifies your history in a very significant way."
But Dr Allan Pacey, a lecturer in andrology at the University of Sheffield and secretary of the British Fertility Society, said: "Although we have removed anonymity, whether or not you know you are donor-conceived depends on whether or not you are told. But I don't think you need legislation. I would be concerned about stigmatising individuals."
Audrey Sandbank, a psychotherapist and consultant with the Multiple Births Association, said of the case: "These [twins] ... had a strong connection. When they met they would have felt like soulmates – particularly as, like all siblings, they shared about 50 per cent of their genes."Reuse content