The child was conceived in the United States by artificial insemination

But this already controversial birth is now posing an unprecedented ethical problem after the 62-year-old, identified simply as "Jeanine", revealed in an interview that her brother Robert is the child's biological father.

The details of this case have shocked French people.

Doctor tricked

Robert's sperm was used to fertilise two eggs donated by a Californian woman: one was brought to term by "Jeanine", the other by the donor.

The two babies were born on either side of the Atlantic within a few days of each other and are now being brought up by "Jeanine" and Robert in the home they share with their 80-year-old mother.

In her interview, "Jeanine" admits that she tricked the doctors in Los Angeles into believing that she and her brother were married.

The man who performed the fertilisation treatment has expressed his disappointment at the news and says that in future he will demand to see couples' marriage certificates.