Japan's Princess Kiko is reportedly pregnant, raising the possibility that the royal family could produce its first male heir in 40 years.
Princess Kiko already has two daughters
Princess Kiko, the 39-year-old wife of Emperor Akihito's second son, is due to give birth in the autumn, Kyodo news said, quoting the Imperial Household.
No boy has been born into the imperial family since 1965.
The current succession crisis has led the government to consider allowing a woman to succeed the throne.
Crown Prince Naruhito, first in line to the throne after his father Akihito, has just one daughter with his wife, Crown Princess Masako.
Currently only males can ascend the Japanese throne
Emperor Akihito has two sons, Naruhito and Akishino
If Naruhito died without a male heir, his brother, Akishino, succeeds
But he has no sons either
Their sister, Princess Sayako, is marrying a commoner so her children cannot ascend throne
Princess Kiko and Prince Akishino currently have two daughters.
The news of the pregnancy prompted applause at a parliamentary committee meeting attended by Prime Minister Junichiro Koizumi on Tuesday.
But Mr Koizumi nevertheless urged the debate on allowing women to succeed the Chrysanthemum Throne to continue.
He wants to present parliament with suggested revisions to the 1947 Imperial Household law by June.
"If we wait, it is uncertain that a boy may or may not be born," he told lawmakers, according to the Associated Press.
"To ensure the stable continuity of Japan's imperial family, we cannot put the issue off any longer," he continued. "It is desirable that parliamentary debate is carried out in a calm, careful manner at the earliest opportunity."
Crown Princess Masako, 42, has been under intense pressure to bear a male heir, and makes few public appearances due to stress that many blame on the succession issue.
If the law were changed, it would put her four-year-old daughter Aiko in line to the throne.
Mr Koizumi said this was another reason not to delay any change.
"Princess Aiko is coming to the age when she will start going to school. It would make great difference for her if her education is given with an assumption she would not become a reigning empress or if she realises she must become empress someday," he said.
Conservatives, both among the imperial household and in parliament, have questioned the plan.
Last week, Foreign Minister Taro Aso called for more debate before the bill is presented to the legislature.
The public, however, is more supportive, although a poll published on Monday suggested 63% backed changing the law, down from 81% a year ago.