Stress of family breakdown and rise of obesity levels blamed as girls' puberty age falls to tenBroken homes, stress and obesity behind girls entering puberty earlier than everUS study finds girls with absent fathers are 2.4 times more likely to develop breast tissue at a younger age'Strong link' between early puberty and early onset of sexual activity and teenage pregnancy
23:03 GMT, 14 June 2012
Scientists say modern relationships are partly to blame, picture posed by model
The stress of family breakdown could be to blame for girls starting puberty at the age of ten, according to scientists.
The average age at which girls start growing breast tissue has fallen over the past 15 years and it usually begins when they are still at primary school.
This is thought to be caused by a hormone imbalance, which in turn has been linked to a number of factors, including rising levels of obesity.
However, experts are increasingly concerned that the strain of modern relationships may also be a key factor.
Professor Richard Sharpe, of Edinburgh University said the trend towards broken families and absent fathers could be triggering the hormone imbalance.
He said long-term stress could also be caused by the higher expectations put on girls to achieve at school and fit in with the crowd.
Studies have shown breast development – the first sign of puberty – begins on average at the age of ten, which is five years earlier than during the 19th century.
Doctors say the risks of this include premature sexualisation of young girls and teenage pregnancy. It is also linked to an increased risk of breast cancer in later life.
Professor Sharpe, group leader at the Centre for Reproductive Health, told the Cheltenham Science Festival yesterday: ‘We are seeing early puberty in situations which we would deem stressful for girls, for example being adopted or growing up without their biological father in the house.
'There may be a stepfather or the child is having to live in two homes. That is all somewhat stressful and it is much more common nowadays than it was.
Higher levels of child obesity is another key factor identified as a reason to earlier onset puberty
‘It may even be that it is all the expectations of the modern world on girls, because there’s been a radical change in what their expectations are.’
Two years ago a study by US researchers found girls of all backgrounds whose fathers had left home were 2.4 times as likely to develop breasts at a younger age.
Many began at nine and some as young as seven, according to a study of 440 girls by the University of California Berkeley.
One explanation is to do with overproduction of the male hormone androgen – which girls naturally produce during puberty – but could be produced in higher quantities and earlier due to stress.
Professor Sharpe said that researchers are looking at ‘societal factors’ to explain why breast development is getting earlier, while menstruation is not.
Breast tissue and body hair are the first stages of puberty, followed by menstruation, but the average age for girls to start their period has been 12-and-a-half since the 1960s.
Professor Sharpe said it was difficult to establish exactly how different hormones were interacting to trigger early breast development.
Dr Tabitha Randell, of Nottingham University Hospitals NHS Trust, also speaking at the festival, said: ‘We need to help parents deal with the physical and psychological consequences of early puberty which are very serious and can very distressing for the child.
‘There is a strong link with early onset of sexual activity when they are not emotionally ready, and with teenage pregnancy for which already have the highest level in Europe.’