Scientists warn of sperm count crisis
Biggest-ever study confirms drastic decline in male
December 5, 2012
The reproductive health of the average male is in sharp
decline, the world's largest study of the quality and
concentration of sperm has found.
Between 1989 and 2005, average sperm counts fell by a third
in the study of 26,000 men, increasing their risk of
infertility. The amount of healthy sperm was also reduced, by
a similar proportion.
The findings confirm research over the past 20 years that has
shown sperm counts declining in many countries across the
world. Reasons ranging from tight underwear to toxins in the
environment have been advanced to explain the fall, but still
no definitive cause has been found.
The decline occurred progressively hroughout the 17-year
period, suggesting that it could be continuing.
The latest research was conducted in France but British
experts say it has global implications. The scientists said
the results constituted a "serious public health warning" and
that the link with the environment "particularly needs to be
The worldwide fall in sperm counts has been accompanied by a
rise in testicular cancer - rates have doubled in the last 30
years - and in other male sexual disorders such as
undescended testes, which are indicative of a "worrying
pattern", scientists say.
There is an urgent need to establish the causes so measures
can be taken to prevent further damage, they add.
Richard Sharpe, professor of reproductive health at the
University of Edinburgh and an international expert on toxins
in the environment, said the study was "hugely impressive"
and answered sceptics who doubted whether the global decline
"Now, there can be little doubt that it is real, so it is a
time for action. Something in our modern lifestyle, diet or
environment is causing this and it is getting progressively
worse. We still do not know which are the most important
factors but the most likely are - a high-fat diet and
environmental chemical exposures."
Researchers from the Institut de Veille Sanitaire, St
Maurice, used data from 126 fertility clinics in France which
had collected semen samples from the male partners of women
with blocked or missing fallopian tubes. The men, whose
average age was 35, did not have fertility problems of their
own and were therefore considered representative of the
general male population.
The results, reported in the journal Human Reproduction,
showed the concentration of sperm per millilitre of semen
declined progressively by 1.9 per cent a year throughout the
17 years - from 73.6 million sperm per millilitre in 1989 to
49.9 million/ml in 2005. The proportion of normally formed
sperm also decreased by 33.4 per cent over the same period.
Although the average sperm count of the men was well above
the threshold definition of male infertility - which is 15
million/ml - it was below the World Health Organisation
threshold of 55 million/ml which is thought to lengthen the
time to conceive. Other European studies have shown that one
in five young men has a sperm count low enough to cause
Combined with other social trends, such as delayed
childbearing which reduces female fertility, the decline in
sperm counts could signal a crisis for couples hoping for a
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