Paternity suit runs into double trouble

It is a paternity suit that not even DNA testing can solve. A five-year-old boy may never know his father's identity because his mother claims she had sex with identical twins at the time he was conceived.

Lawyers admit that the most advanced genetic testing techniques are unlikely to prove which of the twin brothers - in their late twenties - fathered the child. The unprecedented case in Montreal, Canada, is a real-life rerun of a plot twist in Zadie Smith's 2000 novel White Teeth, in which the character Irie Jones has sex with the Iqbal twins on the same day and becomes pregnant.

Whereas siblings usually have enough genetic differences to be told apart, identical twins' DNA is almost exactly the same. Justice Paul Jolin, of the Quebec Superior Court, said of the case: 'There's a high risk that it is impossible to determine who the father is.'

One of the twins, who cannot be named for legal reasons, went to court last summer in the hope of forcing the mother to grant him access to the child. Although his name is not on the birth certificate, he claims he is the only father the boy has known, cared for him every other weekend, provided financial support and was even known to him as 'papa'.

But then the man's relationship with his girlfriend broke down and the visits halted. When he began legal proceedings to prove his paternity, the mother made her claim that she had been sleeping with his twin at around the same time.

The twins have said they knew they were both having sex with the woman, but argue that only one had sex during the period of conception. Both refused to undergo a DNA test: the complainant refused to pay the £335 charge while his brother, who has since married and fathered children, does not consider himself involved in the dispute.

Now, however, Judge Jolin has asked the complainant to take a DNA test by 1 December to ensure he can claim even possible paternity, while his brother may also be tested.

Scientists in Canada have said it is possible for identical twins to have slightly different DNA because of genetic mutations while the embryos are duplicating in the mother's womb at an early stage of pregnancy. But such differences are not detectable with the standard method of testing. Kristine Ashcraft of Genelex, which provides DNA testing, warned: 'There's no way to tell who the father is. They have the same DNA.'

If technology fails to end the mystery, the paternity question may ultimately rest with the judge. Myriam Pamphile, the twins' lawyer, said: 'The other twin is known by the rest of both families as the uncle of the child. The man claiming paternity said he has given financial support to the mother, even when she refused it. He saw the child every two weekends.

'In the best interests of the child, if he had known the first brother to be the father, I would think that the judge would give a decision where he still assumed that responsibility.'

Catherine Bamber, the mother's lawyer, said her client was not committed to either twin. 'The brothers are her friends and had sexual relations with her, but they were never together as a couple,' she said.