Sperm counts are falling dramatically across the industrialized world, and scientists are increasingly convinced that pollution is to blame. Studies around the world have shown that average sperm counts in men have dropped by more than half over the past 50 years.
The British Medical Research Council reports that the fertility of Scottish men born since 1970 was 25 per cent less than those born in the 1950s, with sperm counts continuing to drop by two per cent a year. Other research by the U.S. Environmental Protection Agency shows that, proportionately, a man now produces only about a third as much sperm as a hamster.
Scientists blame hormone-disrupting chemicals that cause cancer and damage the immune system, as well as impairing fertility.
DDT and other pesticides disrupt hormones, as do PCBs, which are used in countless products worldwide, from plastics and paint to electrical equipment. Other components of plastics have been found to cause pollution by hormone-disrupters including phthalates, which have been found in a wide range of foods including baby formula.
Artificial estrogens, used in contraceptive pills and hormone replacement therapy, appear to be changing the sex of half the fish in Britain?s rivers. Scientists and environmentalists are afraid that the chemicals are getting into drinking water and affecting human fertility.
A study funded by the British government examined fish from 10 rivers over the past five years and found ?intersex? males in all of them. Just under half of the male fish had developed eggs in their testes or female reproductive ducts. One tenth were sterile and another quarter were producing damaged sperm.
British water companies say that no hormone-disrupting chemical has ever been detected in drinking water, but scientists say that the chemicals have not been detected because there is no routine testing for them in drinking water, and because the equipment used isn?t sensitive enough. Research in West Germany, using more sophisticated techniques, found small amounts in four out of every 10 samples tested.
Dr. Susan Jobling of Brunel University, who led the research, says, ?Unlike in fish, it is going to take 20 years to see if my children have been affected by developmental exposure to this same cocktail of chemicals.?
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Good nutrition during pregnancy may be a crucial element of male fertility, a new study has found. Folic acid, a well-established birth-defect preventative for pregnant women, together with zinc, which is also involved in DNA synthesis, improves sperm quality in men with fertility problems, according to the study by the University Medical Center Nijmegen in the Netherlands.
Researchers theorized that the two nutrients might affect semen quality. Since enzymes involved in testosterone synthesis also need zinc, supplements of the mineral may stimulate testosterone production, and consequently the volume of sperm, says Regine Steegers-Theunissen, associate professor in obstetrics and gynecology at the Dutch university.
Folic acid, a B vitamin found in leafy green vegetables and legumes, is known to protect against congenital neural tube defects such as spina bifida. Zinc, found in foods like red meat and poultry, is needed for uptake of some folate enzymes.
The researchers studied 108 fertile men, whose wives had conceived within a year of unprotected intercourse, and 103 men with fertility problems of an unknown cause, whose wives had failed to become pregnant and whose semen had a low sperm concentration.
Before the study, both groups of men had similar concentrations of folate and zinc in their blood and seminal fluid. Over 26 weeks, men in both groups followed one of four regimens: daily doses of folic acid and zinc sulfate, folic acid alone, zinc sulfate alone, or placebos.
After treatment, the subfertile men who were given both supplements showed a 74 percent increase in the number of normal sperm in their semen and a 4 percent increase in abnormal sperm. Men in the fertile group had small increases in sperm count when given folic acid plus zinc, or zinc alone, according to the study.
?Both genetics and environmental influences play a part in the complex process of sperm production,? says Dr. William Keye Jr., president of the American Society for Reproductive Medicine. ??The next step is to see whether the effects of nutritional supplements can result in any increase in pregnancy rates.?
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Without men, what will happen to the NFL? In football, teams struggle mightily to win enough games to gain ?home team advantage.? Now psychologists in the U.K. have discovered there?s a scientific reason for this. When they tested soccer players, they found that all members of a squad?especially goalkeepers?have much higher levels of testosterone before a home game than before a game played in another city.
?It is clear there is a big home advantage, and we think testosterone is a major factor that has been overlooked by theorists in the past,? says Sandy Wolfson of the University of Northumbria, who conducted the research with colleague Nick Neave.
?We know testosterone is linked to dominance and aggression in animals,? says Neave. ?We?re trying to tie the results in with territoriality. The idea is that if you're playing at home, you feel you?re defending your own territory. The testosterone surges in the goalkeepers was unbelievable and obviously they?re the ones who are most involved in defense.?
If coaches can use motivational techniques to boost testosterone levels before away games, they should be able to improve their teams? scores, say Neave and Wolfson.
Wolfson and Neave took saliva samples from players one hour before three training sessions, two away games and two home games. The players were matched with a team described as a bitter rival and one classed as a moderate rival. They played each opposing once at home and once away.
The players? testosterone levels were at the male average before the training and before the away games. But they were 40 per cent higher just before the home game against the moderate rival and 67 per cent higher before the bitter rival game they played at home.
Other factors may be involved in the home advantage, such as crowd support, referee bias and familiarity with the playing field, Wolfon says, ?But none of these on their own has been found to have a strong effect.?
To learn more, see ?Men?We?ll Miss ?Em,? click here.
To learn about how one testosterone-loaded male was changed by his out-of-body experiences, read ?Fast Lane to Heaven? by Ned Dougherty,click here.
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