Japan's Princess Kiko gave birth to a boy early Wednesday, providing the centuries-old Chrysanthemum Throne with its first male heir in more than 40 years, the palace announced.

The birth came about an hour after Kiko, 39, was reported to have undergone a Caesarean section. The boy is the third in line to the throne, after Crown Prince Naruhito and Kiko's husband, Prince Akishino.

The arrival of a royal boy forestalled a looming succession crisis for the royal family. Japan's 1947 succession law allows only males to ascend the throne, and prior to Wednesday's Naruhito and Akishino were the only royals eligible for the crown.

CountryWatch: Japan

The boy, the first male heir born in Japan since Akishino in 1965, was born at 8:27 a.m. (2327 GMT Tuesday) and weighed 2,558 grams (5.64 pounds), the Imperial Household Agency said. Kyodo News agency reported mother and child were in good condition.

Kiko, who already had two daughters, was hospitalized on Aug. 16 after showing symptoms of partial placenta previa, in which part of the placenta drops too low in the uterus.

The gender of the baby had been a closely guarded palace secret, though Japanese tabloids speculated the child will be a boy.

The last potential male heir born was Akishino himself, in 1965. Emperor Akihito's eldest son, Naruhito, has a daughter with his wife Masako, but the couple have no sons, meaning there is no one to inherit the throne after he and his brother. Kiko, likewise, had no sons.

The looming succession crunch had prompted serious discussion of changing the law to allow a female to assume the throne. The proposal had the support of Prime Minister Junichiro Koizumi and a majority of the public.

Even before the 1947 law, reigning empresses were rare, usually serving as stand-ins for a few years until a suitable male can be installed. The last reigning empress was Gosakuramachi, who assumed the throne in 1763.

Debate over the succession law was divisive and emotional. Some conservatives proposed a revival of concubines to produce imperial heirs, and others argued that allowing a woman on the throne would destroy a precious Japanese tradition.

News of Kiko's pregnancy — and the possibility of a male heir — in February quickly put an end to the discussions.