Gene tests urged by fertility specialists

By MARTIN JOHNSTON health reporter

Fertility specialists want to use chromosome testing to screen out faulty human embryos and boost the success rate of test-tube fertilisation.

While "efficiency" is the main reason for the planned move, the test would also help to prevent miscarriages and let fertility scientists detect embryos with the chromosome-linked conditions Down's syndrome and Turner's syndrome.

A director of Auckland-based Fertility Associates, Dr Richard Fisher, said last night that his clinic would soon file an application with the National Ethics Committee on Assisted Human Reproduction to begin using the technique.

Called "Fish" - Fluorescent In-Situ Hybridisation - the technique would be used to improve the likelihood of women becoming pregnant from in-vitro fertilisation, or IVF.

The Fertility Associates application was about finding the embryos with normal chromosomes, as they had a much higher chance of implantation in the womb, said Dr Fisher.

The plan was to screen for the worst chromosome abnormalities.

"These embryos never implant and children are never born," he said.

The Fish technique has been used in many places overseas since the mid-1990s.

It involves laying a DNA "probe" against a cell taken from the embryo and watching under a microscope for the probe or marker to glow fluorescently if the right number of chromosomes are detected.

It is already in use here in a pilot study designed to speed the analysis of samples taken from the placentas of pregnant women, but no one has yet been approved to use the technique on embryos.

Fish could also be used to detect the sex of embryos, Dr Fisher said, but that would be done only to test for sex-determined conditions, such as haemophilia and muscular dystrophy, which affect males and are carried by females.

"This is not eugenics. We are not looking for the best and brightest," he said.

Fish testing could be used to screen for a wide range of genetic disorders, such as cystic fibrosis, but Fertility Associates was not applying to test for any of them.

However, Down's syndrome and Turner's syndrome would be detectable.

Dr Fisher said the Fish test would be of most use to older women going through an IVF programme. As women aged, their proportion of abnormal chromosomes increased greatly, reducing their chances of becoming pregnant.

Guy Gudex, clinical director of Fertility Plus at National Women's Hospital, said it was a big ethical and social issue and some social commentators would be concerned that this was "the thin end of the wedge."

"You start off testing for Down's syndrome and other chromosome defects - which most of society doesn't have a problem with - but some people will ask where that will lead to."

Right to Life spokesman Ken Orr said the proposed use of new birth technology was part of a "slippery slope" for fertilisation ethics and he urged doctors to "stop tampering."

"This is the intentional destruction of human life. It is the violation of any chance that an embryo has of living, and that is unacceptable."