Can chemicals slow sperm need we worry?

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spermA recent study published in EMBO Reports provides the latest fuel for fear-mongering about chemicals. Dr. Christian Schiffer of the Center of Advanced European Studies and Research in Bonn, Germany and colleagues tested 96 different chemicals found in many household products, foods, and personal care products to see what effect they might have on human sperm. The impetus for this research was the theory that human sperm production has dropped precipitously over the last four or five decades, and that so-called endocrine-disrupting chemicals might be responsible.

Of these chemicals, thirty were found to disrupt the action of a protein that controls sperms ability to swim, and also diminishes their ability to enter and fertilize egg cells. Although these effects sound serious, there are a couple of caveats.

First, these effects were seen in vitro, that is, in laboratory studies, and not in intact humans or animals. So the value of these results is questionable until more studies are performed.

Second, it is interesting that over two-thirds of the chemicals tested did NOT impair sperm. So what about all the noise we ve been subjected to about so-called endocrine-disrupting chemicals: could it be that those fears are exaggerated? In fact, Prof. Niels E. Skakkebaek, leader of the Danish team involved in this study, was one of the original proponents of the global sperm and fertility decline theory.

Finally, not all experts agree that human sperm production and function have been decreasing, but ascribe supposed changes to poorly designed studies. For example, ACSH advisor urologist Dr. Harry Fisch published a study a few years ago showing clearly that the global decline in sperm counts was largely a myth.

ACSH s Dr. Elizabeth Whelan commented, I was particularly amused by this statement: Considering that male fertility issues occur in nearly 50% of cases involving couples finding it difficult to conceive, this could mean big things for men improving their chances. It surely makes sense that one-half of the sources of fertility problems occur among men however, I strongly doubt that avoiding all chemicals will be of any benefit. More specifically, finding an effect in the laboratory is no proof that it will also be found in humans. This is even weaker evidence than laboratory animal studies that are often mis-applied directly to humans.