While China's one-child policy is imposed by the government, in Japan it has been a voluntary preference for married couples for decades. They claim they cannot afford another child because of high education costs, the responsibilities of rearing children, limited space at home and young parents' greater interest in a world outside family life. The two countries face similar consequences - a fast-greying population and often excessive spending on the only child.
Lately in Japan, big-spending young parents have been seeking out new baby products and services that their own parents never knew.
The cheerleaders of this consumerism are several new baby magazines showcasing a flood of fresh products - many via the internet. Aka-sugu, for example, is one of the most popular baby-shopping magazines, boasting a huge gallery of daily baby-care goods and fashionable babywear. That includes 'rare imports' such as cotton-knit baby blankets - the same brand used by celebrities - priced at 8,000 yen ($564) and limited-edition French leather baby shoes for 16,000 yen.
Some magazines also develop their own products based on reader feedback. Tamago (Egg) Club offers an 'I am a mother' wrist strap with a printed illustration of a pregnant woman. Women wearing the bands hope to be treated more kindly, on trains, in banks and in restaurants, for instance.
'Times have changed,' said one new grandmother in her late 50s in my neighbourhood. 'Young mothers like my daughter simply continue their fun life just as before.' During pregnancy, her daughter went shopping, ate gourmet dinners and enjoyed 'maternity concerts' and 'maternity swimming lessons'. With a lifelong love of shopping, she has also delved into the world of catalogues and the internet following the birth of her daughter a year ago.
Not all the items on her recent shopping list were expensive, however. They included a colourful plastic bottle with a straw, an embroidered cover for the car's child seat, a Nuby-brand dummy set from England and lemon-flavoured fluoride spray for teeth.
Some baby goods have also regained popularity under new foreign names. Rattles are now called by their English name, instead of the traditional Japanese gara-gara; a blanket is now an afghan. Marketeers also coin new, exotic terms - such as ku-fan for a baby-carrying basket - to inspire young shoppers.
The strategy works - one colourful Swedish plastic baby bib, sold under the mysterious name of su-tai, is selling 100,000 pieces a year now.
But all these new names are proving something of a puzzle for the poor grandparents eager to buy presents for their new grandchildren.