Scientists warn
that such young girls are ill-equipped to
cope with sexual development when they are
still at primary school.
“We were very
surprised that there had been such a change
in a period of just 15 years,” said Anders
Juul, head of the Department of Growth and
Reproduction at the University hospital in
Copenhagen, a world leader in the study of
hormones and growth.
“If girls
mature early, they run into teenage problems
at an early age and they’re more prone to
diseases later on. 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.”
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 bottles.
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.
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 for boys.
The
international standard for normal puberty in
white girls was set in the 1960s at 12Å for
the age when periods begin and at about 14
for boys when their voices break and their
growth surges.
A more
recent consensus in Britain has proved
elusive. “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.”
Sharpe said
boys had also been affected by the
phenomenon. Choir schools have reported an
increasing number of boys dropping out
because their voices had broken at the age
of 12 or 13.
Richard
Stanhope, an expert in hormonal disorders in
children who recently retired from Great
Ormond Street hospital, said specialists in
his field believed they were seeing more
children going through early puberty.
“All the
things we experience as teenagers are
difficult enough to cope with, but when it
happens at 10 or 11 it is much worse,” he
said.
“These
children are also at a much higher risk of
being sexually abused because it is hard for
some adults to understand and behave
appropriately towards them.”
Girls who
reach puberty early often find themselves
teased at school. “I had to wear a bra at
9,” said one girl, who did not want to be
named. “I used to pretend to be ill to get
out of changing for PE.
“The worst
part was men coming on to me as though I was
an adult when actually I was 11.”
A study
published in the journal Public Health
Nutrition last Friday showed a link between
high meat consumption and earlier puberty in
girls.
Researchers
at Brighton University found that 49% of
girls who ate meat 12 times a week at the
age of 7 had reached puberty by the age of
12 1/2, compared with 35% of those who ate
meat four times a week or less
