A study of Vietnamese families credited whistling with getting babies out of diapers by just nine months.
Swedish researchers in the Journal of Pediatric Urology reported that potty training in Vietnamese families started almost from birth, with mothers making a whistling sound when their child gave a sign that they needed to go, the 'Daily Mail' reported.
The children associated the whistling with urinating, and by the age of nine months, they were able to keep dry - as long as they were regularly reminded to sit on their potty.
The researchers said that while Western babies are potty trained later now than in the past, early toilet training has traditionally been regarded as a badge of pride in Vietnam.
As well as saving on the cost of nappies and the time spent changing them, learning to control the bladder very early in life may be better for urinary health, researchers said.
In the past, potty training often started before the age of one. But today's mothers are advised to wait until their child is 18 months to two years old - and many begin even later.