Creation of human 'she-males' angers IVF experts

By STEVE CONNOR

An experiment that created human "chimeras" by merging male and female embryos in a test tube has been condemned as scientifically vacuous and ethically questionable by leading proponents of research into IVF.

A team of privately funded researchers created the hermaphrodite chimeras- a mix of cells from two separate embryos - as part of a study into ways of treating inherited disorders but their colleagues in the field of reproductive medicine have strongly denounced the study.

The chimeric embryos, which contained both male and female cells growing side by side, were not allowed to live beyond six days after conception when they were still microscopic balls of cells. Yet many scientists believe that the experiment should never have been carried out.

"It doesn't make any sense to me," said Alan Trounson, a leading authority in IVF research at Monash University in Melbourne, who publicly criticised the study when it was presented at the European Society of Human Reproduction and Embryology in Madrid.

"I think it's a flawed experiment. Unless you can be certain that you're doing good with something, you shouldn't do it at all. It is the Hippocratic principle of doing no harm," Professor Trounson told the meeting.

"I think we've got to stand up and say we don't understand the point of this and we don't think it should proceed unless you have a much better reason.

"It is essentially trivial science that's unlikely to be useful. It's difficult to argue why it should be done to the public," added Professor Trounson.

The study was carried out at the Center for Human Reproduction in Chicago by a team led by Norbert Gleicher, the founder of the privately-funded institute, who is also a visiting professor of obstetrics and gynaecology at Yale University.

Professor Gleicher injected embryonic cells taken from male embryos into "high quality" female embryos that were about three-days old. Some of the chimeric embryos continued to develop apparently normally for three more days at which time the male cells had divided and spread throughout the female embryo.

Professor Gleicher explained that he deliberately chose to insert male cells into a female embryo in order to make it easier to see whether the injected cells had managed to integrate into the recipient embryo n he looked for the presence of the male Y chromosome.

He emphasised that he had approval from an in-house ethical committee and also took outside legal advice. He said the experiment would never be done on an embryo that he intended to implant into the womb. It was only conducted as part of an investigation into treating singe-gene disorders, such as muscular dystrophy, by introducing healthy cells at an early stage of embryological development.

"If you had an afflicted embryo and if you are able to introduce just 15 per cent healthy cells, you may be able at that point to treat single-gene disorders," Professor Gleicher said.

"Normally you would do this with embryos of the same sex, but we did it with different ones as a model. Our primary purpose was to see if this was feasible and I think we have convincing evidence that the answer to that is yes," he said.

"Now we need to take further steps and that probably means going back to animal experiments," he added.

However, other scientists were not convinced. Lyn Fraser, professor of reproductive biology at King's College London, said: "For me it's a non-starter. It's a biologically questionable approach.

"There is no way you can ensure that so-called good cells would get to the organ in question. There is no guarantee it will work," she said.

In ancient Greek mythology, the Chimera was a creature that was formed by combining a lion, a goat and a snake. In science, a chimera is an organism that contains the cells of two genetically distinct individuals. The most famous example was the 'geep', which was created by merging the embryos of a sheep and a goat.

Human chimeras can be created naturally when two embryos of siblings fuse spontaneously within the womb - an exceptionally rare event.

- INDEPENDENT