Girls as young as as seven and eight are beginning their periods and showing other signs of puberty, new research has found.
The findings add to the evidence that the age at which girls reach puberty is falling dramatically.
Some experts believe that growing levels of obesity are believed to be the cause of the rise, while others link the problem to high levels of chemicals found in the linings of modern food containers such as baby bottles and tin cans.
According to doctors, extra fat tissue encourages young bodies to produce hormones which kickstart sexual changes.
Researchers in the US have found that ten per cent of girls aged seven have developed breast tissue, which is one of the signs of puberty. Although there are no official figures for the numbers of seven and eight year old girls starting puberty in the UK, doctors in Britain have backed up the findings, saying that they are treating numbers of girls aged seven and eight with puberty problems.
Health experts warn that early exposure to oestrogen has serious health implications because it put girls more at risk of breast cancer and heart disease.
The US study, published in the journal Pediactrics, give further signs of a trend which has seen the age of puberty fall dramatically over the past two centuries. By the 1950s it had fallen from around the age of 15 to 11 or 12, and researchers from Denmark recently found that girls were starting puberty a year earlier than they would have done 20 years ago.
Does this research back up your own experience?
Did your daughter start her period earlier than you expected?