New Delhi, Dec. 1 -- Japan's beloved Princess Aiko is often cheered like a pop star.

During a visit to Nagasaki with Emperor Naruhito and Empress Masako, the sound of her name being screamed by well-wishers along the roads overwhelmed the cheers for her parents.

As she turns 24 on Monday, her supporters want to change Japan's male-only succession law, which prohibits Aiko, the emperor's only child, from becoming monarch.

Along with frustration that the discussion on succession rules has stalled, there's a sense of urgency. Japan's shrinking monarchy is on the brink of extinction. Naruhito's teenage nephew is the only eligible heir from the younger generation.

Experts say the female ban should be lifted before the royal family dies out...