Genetic tests have established that the white woman who gave birth to black twins after an IVF mix-up is the biological mother of the babies.

The results mean that doctors implanted the correct egg into the right patient.

However, the tests have suggested that they used the wrong sperm to fertilise the egg.

Mrs A is their biological mother, but...Mr A is not their biological father

Dame Elizabeth Butler-Sloss

Both the white and black couples involved in the case were receiving IVF treatment at the same clinic.

Neither the couples nor the clinic can be identified for legal reasons.

During the case the white couple have been referred to as Mr and Mrs A while the black couple have been referred to as Mr and Mrs B.

Statement

The test results were revealed in a statement issued by High Court Family Division President Dame Elizabeth Butler-Sloss, who has the task of sorting out the legal issues raised by the case, including paternity and custody.

In her statement, she said: "Genetic testing has established Mrs A is their biological mother, but that Mr A is not their biological father.

"Once the NHS trust responsible for the clinic became aware of the possibility of an error, it undertook an investigation which is continuing.

"The trust has identified a man, Mr B, who it is thought might have provided the sperm to Mrs A. He and his wife were receiving fertility treatment at the same clinic.

"The circumstances of this case raise difficult issues relating to the privacy of both families and medical confidentiality."

Dame Elizabeth added that the she will give her ruling on the outstanding issues "in due course".

Government inquiry

The government has already launched an investigation to find out how the mix-up occurred.

The inquiry was revealed by ministers in the House of Lords earlier this month.

Ministers said they had been asked to keep the investigation secret by the judge.

Speaking at the time, Health Minister Lord Hunt said: "We have arranged for a very thorough independent investigation to be carried out.

"At last week's court hearing the judge directed the government that it should not announce it had set up an investigation.

"This was because she was concerned to keep discussion of this case to a minimum to protect the families and children concerned."