Scientists appear to have found a way that someday could allow women to become mothers after they no longer can produce viable eggs, a potential advance in breaking the last great barrier to fertility treatments.
Theoretically, the method could create an unlimited supply of eggs for an infertile woman and allow her to have a child at a much older age. However, experts tried to play down that possibility, saying they strongly discourage post-menopausal motherhood on ethical and practical grounds.
The technique, described Monday at a conference of the European Society of Human Reproduction and Embryology in Lausanne, involves taking a cell from an infertile woman's body, and inserting it into an emptied donated egg. The resulting egg contains the genetic material of the woman wanting the baby, not of the donor.
Scientists warned that the work is still in the preliminary stages, and it could be years before the technique produces a healthy baby, if ever. When they fertilized the manufactured egg with sperm, it divided once, then collapsed.
Dr. Gianpiero Palermo, a professor of embryology at the Center for Reproductive Medicine and Infertility at Cornell University, said that besides older women, his technique could help those who can't use their own eggs, either because they don't have any or because their eggs are no good.
Such women could include those whose ovaries are removed before cancer treatment, those who were born without ovaries or women who reach menopause at a young age.
Some Say Potentially Revolutionary
Prominent fertility researcher Dr. Zsolt Peter Nagy, who was not connected with the project, said the technique potentially is one of the most important advances in fertility treatment ever.
Fertility treatments took a major step forward in 1978, when a team led by Robert Edwards and Patrick Steptoe conquered Fallopian tube problems with the introduction of in vitro fertilization, where the egg is fertilized outside the body and implanted in the womb.
Then, in 1992, while he was working in Belgium, Palermo circumvented the failure of sperm to swim to the womb by injecting the sperm directly into the egg — a technique called ICSI.
The problem of declining egg supply as women age has probably been the biggest major challenge in fertility treatment since then, experts say.
"I am sure one day this will work," said Nagy, scientific director at the Central Research Clinic of Human Reproduction in Sao Paulo, Brazil. Nagy is pursuing similar research.
"And if it does, it will be the biggest development, after IVF and ICSI," he said.
Edwards called the research "promising."
Others Say Genetic Abnormalities Could Occur
Others were more skeptical that manufactured eggs could produce healthy babies anytime soon, saying the technique would likely create gross genetic abnormalities. Scientists believe that DNA deteriorates with age and fear that the older the cell, the more likely the chance of major defects.
All people inherit two sets of chromosomes from their parents - one from their mother and one from their father. Normally, all the cells in the body, except the sperm and the egg, have two copies of each chromosome, which contain the genes.
A mature egg contains only one set of each chromosome. When a cell from elsewhere in the body is inserted into an emptied egg, it then has two sets.
To make the egg viable for fertilization, the scientists had to get rid of one of the sets of chromosomes. An electric shock split the pairs in half and prompted the egg to expel the unwanted set of chromosomes, making it suitable to receive the sperm.
Roger Gosden, a fertility pioneer from McGill University in Montreal, Canada, said Palermo's technique was "plausible."
"If there's a way we can help people have a genetic child rather than a donated egg, then we should. This is interesting science, it's very preliminary, but who knows?" he said.