A woman has given birth to her own grandchildren after acting as a surrogate mother for her daughter and son-in-law, it emerged yesterday.

The 46-year-old woman agreed to carry the babies after the couple from Ilford, Essex, failed to find anyone in Britain ready to help. The boy and girl were born by caesarean section in Gujarat, India, a few days ago.

The arrangement, though extremely rare, would be legal in this country, although neither the Department of Health nor its Human Fertilisation and Embroyology Authority could say yesterday how often it may have happened.

The couple were able to use IVF treatment to produce embryos but the woman, aged 26, could not carry them because of a rare condition causing the uterus to develop abnormally.

Nayana Patel, a fertility doctor in Gujarat, who carried out the IVF treatment, said: "The grandmother offered to help them as they really wanted a baby. She was totally healthy during the pregnancy.

"The whole family is really happy. They say they are not just over the moon but on Mars."

Neither baby had yet been named yesterday. The couple are expected to return to Britain within two months.

Alison Murdoch, a professor and head of the Newcastle Fertility Clinic at Life, said: "This is a gift of life within a family. Potentially the ethical issues may be less than with an unknown surrogate."

Cots, a charity advising surrogate mothers and infertile couples, says most surrogates derive great pleasure from knowing they have altered people's lives for the good.

But Josephine Quintavalle, of Comment on Reproductive Ethics, said it was "not ideal" for a grandmother to give birth to her grandchildren; the children would be confused when told how they were born.

Criticism also came from the anti-abortion charity Life. Nuala Scarisbrick, a trustee, said the children's welfare had been put after everyone else and familial boundaries blurred.

"Once again the IVF industry has gone too far by changing the natural order of things beyond all recognition," she said.