Japanese doctors have developed an in vitro fertilization technique that could allow the wives of HIV-infected husbands to give birth to healthy babies.

The method, developed by doctors at several institutions, including Ogikubo Hospital and Keio University, aims to completely remove the human immunodeficiency virus from sperm before it is used to fertilize an egg in vitro, to keep the chances of infection to a minimum.

Kenichi Tanaka, an obstetrics and gynecology professor at Niigata University, plans to compile guidelines governing the implementation of the technique before the end of the year, after other relevant parties have examined matters such as safety and ethics.

Tanaka headed a research team of the Health, Labor and Welfare Ministry that supported development of the method, which eliminates large impurities from sperm in advance by adding a liquid reagent called percoll to the sperm and placing it in a centrifuge.

The process separates sperm from HIV, with the normal sperm sinking into the bottom and the small and lightweight virus rising to the level near the surface of the liquid. The sunken sperm is then recovered for use in a process that sees a human egg fertilized outside a woman's body.

Medical experts say that in the wake of progress in the development of medicines to treat those infected with HIV, there are growing numbers of virus-infected people who wish to have babies.

In the early 1990s, according to Dr. Hideji Hanabusa of Ogikubo Hospital in Suginami Ward, Tokyo, "It was the duty of doctors to persuade people (infected with HIV) to give up having babies."

Hanabusa, head of the hospital's blood department, has long been associated with the treatment of people with AIDS.

The situation changed in 1996 when a method of treating patients by having them take a combination of newly developed medicines brought about remarkable results and contributed to a sharp decline in the percentage of people dying of AIDS.

Italy started early in artificial insemination using sperm free of HIV. In about 2,000 cases reported thus far, there has been no incidence of infection to either the mother or the baby.

However, doctors such as Hanabusa who participated in the development of the Japanese technique have tried to improve on the Italian method, after concluding it did not completely remove the HIV virus.

They organized a research team in 2000 to work on ways to keep the separated virus away from sperm in each stage of treatment and combined it with an ultra-sensitivity inspection method used to check the level of genes.

This made it possible for them to detect minute amounts of HIV, measuring just 1 ml. They also opted for in vitro fertilization to minimize the danger of infection.

They used the method for two babies born at Niigata University Hospital. In both cases, neither mother nor baby were infected with HIV.

The university said that a third woman is currently pregnant.

Doctors at Keio University Hospital have begun treating another woman, and Kyorin University is expected to follow Keio's lead soon.

Hanabusa said about 30 couples are waiting for the treatment throughout Japan.

The husband and wife must both receive counseling before they agree to submit to the process of in vitro fertilization and the ethics committees of the hospitals using the new method should approve it in advance, according to Hanabusa.

Tanaka, a professor at Niigata University, plans to establish guidelines within the year that doctors can follow in using the method, saying, "I want this technique to take firm root as a system of medical care."