Smartphones and tablets are triggering early puberty in boys, according to new research.

The researchers say the devices emit blue light that reduces melatonin, a hormone that delays sexual maturity.

The study found that blue light-emitting devices also fuel reproductive hormones and cause physical changes in the ovaries.

Scientists add that children should not use digital devices before bed.

Although inconclusive, we would recommend that use of blue-light-emitting devices be minimized in prepubertal children, especially at night.

On average, girls begin puberty around the age of 11 and boys at 12.

Obesity, chemicals and stress have been the main culprits.

Now, experiments have shown that long periods of exposure to blue light accelerate puberty in female rats.

The time point is roughly equivalent, relative to life expectancy. Hormonal and ovulation changes during prepuberty and puberty are also comparable.