London - Boys are hitting puberty up to two years earlier than in the past – with some starting to show the first signs of maturing as young as six, according to doctors.

Although it is well-documented that girls are hitting puberty younger, the study is one of the first to suggest that boys are also growing up earlier.

Data gathered from 4,000 boys across the US revealed that, on average, white and Hispanic boys go through puberty around the age of ten, while the average age is nine for black boys.

Researchers working for the American Academy of Paediatrics said that a similar trend had been noticed in other countries, including the UK.

The doctors who volunteered for the study had examined young male patients for signs of puberty.

Nine percent of white boys showed some signs of puberty at six, as did almost 20 percent of black boys and seven percent of Hispanics, the AAP’s annual conference heard.

Overall, the average age of the onset of puberty was 18 months earlier than the long-considered figure of 11.5 years for white boys and two years earlier for black children, who had been thought to start developing aged 11.

The reasons for the shift are unclear but experts warned the results could be skewed because the doctors had volunteered to take part, so they might have had a special interest in the topic because they had more patients going through early puberty than most. - Daily Mail