By Alison Abbott

The Leopoldina, Germany's national academy of sciences, has published a report strongly recommending that preimplantation genetic diagnosis of early embryos be allowed by law when couples know they carry genes that could cause a serious incurable disease if passed on to their children.

The report, published on January 18, is "about making it possible for a woman to decide" whether to undergo the preimplantation genetic diagnosis procedure "according to her own conscience," says ethicist Hans-Peter Zenner at the University of Tübingen, who headed the panel of authors.

The report concludes that there is "no necessity for the state" to interfere with such personal decisions.

Diagnosis in-vitro

In preimplantation diagnosis, eggs are fertilized in vitro and allowed to develop for five or six days to the so-called blastocyst stage. One or more cells are then removed to check for chromosome damage. Only healthy blastocysts are implanted into the mother.

Many countries, including the United States and most members of the European Union, allow the procedure. Only a very few, including Austria, explicitly ban it.

In Germany, the procedure was considered to fall under the country's embryo-protection laws--and to be banned--but last July the federal supreme court ruled that it did not. It acquitted a Berlin gynecologist who carried out the procedure for a number of couples at high risk of passing a serious genetic disease to their offspring, and reported himself to the authorities in 2006.

The Leopoldina report concurs with this ruling. It reasons that healthy embryos are not destroyed during preimplantation genetic diagnosis and so the embryo-protection legislation cannot be relevant to this procedure.

Designer-baby fears

In October, German chancellor Angela Merkel agreed to a free parliamentary vote on the issue, and announced that she personally supports a ban. Critics of preimplantation genetic diagnostics fear it will encourage designer babies, with parents trying to select for eye or hair color. The issue is particularly sensitive in Germany where eugenics was practiced in the Nazi era.

To support parliamentarians in their decisions, the Leopoldina decided to prepare an expert position paper on preimplantation genetic diagnosis and make recommendations about how it should be regulated. A group of 13 academic experts in reproductive medicine, human genetics, developmental biology, ethics and law drew up the report.

The report says that preimplantation genetic diagnosis should be allowed in cases where a couple want to have a child, but a pregnancy is likely to lead to a baby with a serious and incurable genetic disease, including those that first emerge in adulthood. It should not be allowed in any other circumstances.

It also recommends that Germany should establish an authority, along the lines of the UK Human Fertilisation and Embryology Authority, to control the procedures, to assess each case and ensure that parents are suitably advised.

The report supports its recommendations by referring to legal inconsistencies in Germany in the selection against genetic disease. Doctors are allowed to preselect sperm for in vitro fertilization to exclude sperm carrying chromosomal damage. And women are allowed to abort a fetus that is proved by in utero tests to have a genetic disease. The report points out that abortion is a greater psychological burden for women than preselection of a healthy embryo to carry through pregnancy.

It also notes that many German couples go to neighboring countries such as Belgium for preimplantation genetic diagnosis, and would continue to do so if it were banned in Germany.

According to the report's estimates, the restricted permission it advocates would result in just a few hundred cases of preimplantation genetic diagnosis each year--and would not open the floodgates as some critics have claimed.

Reports from the Leopoldina are politically influential. The parliamentary vote on how to regulate preimplantation genetic diagnosis is expected in the next months.