Japan's Princess Kiko gives birth to boy

TOKYO, Sep 6 (Reuters) Japan's Princess Kiko gave birth today to a baby boy -- the first male heir to be born into the ancient royal family in more than four decades, the Imperial Household Agency said.

Kiko, 39, the wife of the emperor's younger son, Prince Akishino, had given birth, the agency told reporters.

The child, third in line to the throne after the crown prince and Akishino, was delivered by Caesarean section after pregnancy complications.

The birth will likely derail debate on revising the 1947 imperial succession law to let women inherit the Japanese throne. No royal males have been born since the baby's father in 1965.

Crown Prince Naruhito, the emperor's elder son, has one daughter, 4-year-old Princess Aiko, who under existing law cannot ascend the throne.

REUTERS DH PM0534