Women using donor eggs can pass on their DNA to baby

InFeRTILe women who use donor eggs to have a baby pass on their own DnA to the child, scientists have discovered.

Their finding overturns the belief that such babies would inherit their genetic make up only from the father and the donor.

Researchers have now proved that the mother makes her own contribution, via secretions from the womb.

The remarkable discovery may help explain why many children born from donor eggs look and behave like the birth mother. It could lead to suggestions that such children have three genetic parents.

experts say the breakthrough will boost the self-esteem of mothers who have been unable to conceive a baby using their own eggs.

Fertility doctors had long suspected that it was possible for a woman carrying an implanted embryo to pass on her DnA but this is the first scientific proof. Specialists at a clinic in Valencia, Spain, found that secretions from the mother’s womb penetrated pre-implanted embryos, influencing their development.

By extracting fluid from the wombs of ten women soon after the fertilised donor eggs were implanted, Dr Felipe Vilella and Dr Carlos Simon established that maternal genes were passing into the foetus.

however, these are merely DnA fragments, not a full set of genes, they say i n a study published the medical journal Development.

Dr Simon and Dr Vilella, whose IVI clinic is popular with British couples, observed that fragments of DnA, known as hsa-miR-30-d, are secreted by the mother’s womb lining and absorbed by the embryo.

Technically it could be argued that children born as a result of egg donation have three parents as the child will carry DnA from the father, the egg donor and the woman carrying the baby. But the Spanish researchers say that what is being transmitted by the mother to the foetus is not full DnA.

Dr Vilella said: ‘These findings show us that there i s an exchange between the womb and the embryo which was previously not known.

‘ It i s something that we already suspected as a result of the coincidence of certain physical characteristics between mothers and children born through egg donation.

‘It has been noted children of [ donor egg] mothers who smoked during pregnancy or were obese in pregnancy were at greater risk of copying their mother but we didn’t know why.

‘now we believe we have the answer. on the positive side, they might pass on artistic temperament or certain physical features that can be a bond between mother and child.’

Professor nick Macklon, of the Complete Fertility Centre at Southampton hospital, said: ‘This is an amazing discovery. We have suspected this for as long as 20 years but we have never been able to prove it.

‘I tell a lot of our women who have egg donation that I believe they give something to the baby they are carrying. now I can tell them I was right.

‘We know that women who have babies by egg donation bond with their babies as well as any other mother. But there is something about knowing that you played a part, even small part, in the genetics of inheritance. That you have passed something of yourself to the baby, even if it wasn’t your egg.’