The latest generation of girls is reaching puberty before the age of
10, a new study suggests, raising fears they may also begin sexual activity
Scientists have found that the
average age that breast development begins is now nine years and 10 months –
almost a year earlier than a previous study in 1991.
They have yet to discover the
reason behind the phenomenon but believe it could be linked to unhealthy
lifestyles or exposure to chemicals in food.
The study was carried out in
Denmark in 2006, the latest year for which figures were available, but experts
believe the trend applies to Britain.
Findings similar in the US
Data from America also points to
the earlier onset of puberty.
Scientists are worried that young
girls are ill-equipped to cope with sexual development when they are still at
primary school – and that exposure to hormones earlier could increase their
risk from breast cancer.
“We were very surprised that there
had been such a change in a period of just 15 years,” Anders Juul, head of the
Department of Growth and Reproduction at the University hospital in Copenhagen,
told the Sunday Times.
“If girls mature early, they run
into teenage problems at an early age and they’re more prone to diseases later
“We should be worried about this
regardless of what we think the underlying reasons might be.
“It’s a clear sign that something
is affecting our children, whether it’s junk food, environmental chemicals or
lack of physical activity.”
The link between puberty and chemicals
Hitting puberty early can mean
longer exposure to oestrogen, which is a factor in breast cancer. There is also
a greater risk of heart disease.
A number of artificially produced
chemicals have been blamed for interfering with sexual development, notably
bisphenol A, a plastic found in the lining of tin cans and babies’ feeding
Mr Juul’s research team is now
testing blood and urine samples from girls in the study to see if a direct link
can be drawn between early sexual maturation and bisphenol A.
The role diet plays
Another factor in puberty could be
diet. Children are eating more than previous generations and growing bigger —
and in many cases becoming obese.
There has been a steady lowering in
the onset of puberty. In the 19th century, it was at about 15 for girls and 17
The international standard for
normal puberty in white girls was set in the 1960s at 12 for the age when
periods begin and at about 14 for boys when their voices break and their growth
A more recent consensus in Britain
has proved less conclusive.
“Although we don’t have clear data
here, there is evidence the same thing [as in Denmark] is happening for reasons
that we don’t understand,” said Richard Sharpe, head of the Medical Research
Council’s human reproductive sciences unit in Edinburgh.
“We don’t know if this is the
result of better nutrition or environmental factors, but it does create social
problems for girls who are already living in a sexualised society.”