When Yasuto Katagiri asked New York's Columbia University in February to perform a heart transplant on Hoku, his 2-year-old son suffering from a rare form of heart disease called restrictive cardiomyopathy, the university had to turn him down because its 5 percent limit for accepting foreign transplant patients had already been reached.

Fortunately, his son was eventually accepted at Loma Linda University Medical Center in California, and Katagiri will begin raising donations to cover the estimated ¥100 million the operation is expected to cost, according to the nonprofit Japan Transplant Recipient Organization.

But Katagiri is one of many parents of sick children who question why they have to look overseas for a life-saving operation.