Several recent research studies have pointed to declining sperm levels in mammals, including men. A study from Finland - a nation until now lauded for healthy & voluminous sperm counts - was particularly conclusive. It studied the sperm levels in the testes of men removed immediately after death (previous studies measured sperm counts from ejaculate, which can vary enormously according to the time that has lapsed since the last ejaculation) and found that:

• only 26.9% of the men who died in 1991 had had normal sperm production, compared to 56.4% in 1981

• men’s testes were reducing in both size and weight

• According to the Worldwide Fund for Nature (WWFN) there has also been an increase in:

• cryptorchidism (undescended testicles) in England and Wales (doubled between 1962 and 1981), increasing the risk of testicular cancer

• enlargement of the prostate gland, which now afflicts 80% of men by the age of 70 in Western countries, and

• prostate cancer, which is associated with sperm abnormalities and is now the most common cancer in the US

The jury is still out as to the principal cause of these reproductive abnormalities but, commenting on the research:

• Professor Smithson of Leicester’s Institute of Environmental Health opined that concentrations of oestrogenics* in water were too dilute to pose a threat and called for more research into the effects of contaminants in the food supply and of changes in diet

• Gwynne Lyons of the WWFN identified pollution as the main likely cause, particularly phthalates (used to soften plastics and as bases for inks), and pesticides. She suggested that the damage was done in the womb and during breastfeeding, when the mother passes body fats containing PCBs, phthalates, pesticides and other chemicals to the baby

The number of couples living in countries with low sperm counts who are unable to conceive is also rising. In more than 70% of the cases, sperm abnormalities have been found to be the root of the problem.

* chemical compounds which mimic the effects of the female hormone oestrogen

Medical Research Council scientist Dr Richard Sharpe blamed oestrogenics for the drop in male sperm counts and explained that the damage was most likely done during the first three months of life in the womb. A man's ability to produce sperm is determined in the first few weeks of life by the sertoli cells which govern the masculation of the male in utero.

Richard's advice was to avoid all foods wrapped or packaged in plastic, all drinks in plastic containers and any foods containing soya. Soya also mimics the effects of the female sex hormone oestradiol, but contains even higher levels of oestrogen.

See also The case for going commando