A Hokkaido woman gave birth to a boy last year using fertilized eggs frozen in 1995, which may be the longest time in Japan that such eggs have been used after being in storage, according to her doctors.

Amid rising concerns about the safety of using frozen eggs stored over a long period, news of the latest birth, made public Tuesday, may give hope to cancer patients who become sterile after undergoing treatment or to people who have repeatedly failed with in vitro fertilization.

Although frozen fertilized eggs can be stored permanently with a minimum of damage, there have been few reported cases of successful births using fertilized eggs stored for a long time.

"At the very least, we were able to confirm that freezing and storing (egg cells) is safe for six years," said Atsushi Azumaguchi of Tonan Hospital in Sapporo.

The findings are to be reported Oct. 1 at a Tokyo meeting of the Japanese Society of Fertility and Sterility.

According to the doctors, the eggs were fertilized in an in vitro procedure in March 1995, but the couple decided to stop pregnancy attempts due to previous failures and had them frozen. But the woman, in her 40s, and her husband decided to resume trying in June 2001 after the hospital asked the couple if it should discard the eggs.

She gave birth in February 2002, the doctors said. The mother and baby are both reported to be in good condition.