The Japan Times Online - Princess Kiko gives birth to a boy
So, finally there is a male grandchild for the Emperor in the Japanese royal family, so the pressure is off Crown Princess Masako to have to have another child. (Her story of stress caused by marrying into a suffocating royal lifestyle is a bit like that of Princess Diana; apart from Masako being academically very smart, successful at a challenging career before marriage, and having a husband who supports her still. OK, almost no resemblance at all really.)
A brief history of the problems caused by having only male heirs to the emperor is set out in this article. Some extracts:
Emperor Meiji (1852-1912) had no male heir with his wife but had 15 children, including five males, with five concubines. Of the five, four died before reaching adulthood, and the one who survived became emperor.
Here's a photo of Meiji. Doesn't look too happy; maybe choosing which concubine to sleep over with gets you down. (Or maybe it's just that it wasn't fashionable in that century to smile for photos.)
Back to the article:
But Emperor Hirohito (1901-1989), known posthumously as Emperor Showa, refused to have a concubine, which led to the postwar abolition of the system. According to Otabe, Emperor Showa wanted to have a close family atmosphere such as might be found in a Western royal family.
And how's this for a let down in your status:
Soon after Japan's 1945 defeat in World War II, 11 families on the collateral line, which served as a safety net to produce male heirs for the Imperial family, lost their Imperial status and became ordinary citizens.
I wonder what happened to those families. Down to the unemployment office?