Why Men's Sperm Counts Are Falling: It's Mom's Fault!

Twenty years ago, Danish scientist Niels Skakkebaek of the University of Copenhagen noticed that sperm counts of men had fallen about half over the past 50 years. 
Sperm counts in the 1940s were averaging above 100 million sperm cells per milliliter. By the 1990s, however, that number had dropped off to 60 million per ml. Now, some 15 to 20% of young men have much less: 20 million per ml.
What could be the cause? Studies point to a startling potential culprit: mothers (or more specifically, what they do while pregnant).

A number of studies point to a connection between early development in the womb and male reproductive problems in later life, especially low sperm counts. For example, men whose pregnant mothers were exposed to high levels of toxic dioxins as a result of the 1976 industrial accident in Seveso, Italy have been found to have lower-than-average sperm counts. But men exposed to dioxins in adulthood showed no such effect. Another study found women who ate large amounts of beef during pregnancy, a diet rich in potentially damaging chemicals called polycyclic aromatic hydrocarbons (PAHs), had sons with relatively low sperm counts. But eating beef as an adult man shows no similar impact.

Meanwhile, studies of migrants between Sweden and Finland, showed that a man's lifetime risk of testicular cancer tends to follow the country he was born in rather than the country where he was brought up. It was his mother's environment when she was pregnant with him, rather than his own as a boy or as an adolescent, that seems to have largely determined a man's risk of testicular cancer.

One of the strongest pieces of evidence in support of this idea comes from studies of people who smoke. A man who smokes typically reduces his sperm count by a modest 15 per cent or so, which is probably reversible if he quits. However, a man whose mother smoked during pregnancy has a fairly dramatic decrease in sperm counts of up to 40 per cent – which also tends to be irreversible.


From the Upcoming ueue, submitted by sshuggi.

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While a lot of the terror about environmental synthetic estrogens is overblown, I've read a few very large studies that show a lot of historical correlation between areas with greatly increased environmental estrogens (especially since The Pill came out, and women started flushing them down the toilet to dispose of unwanted ones) and decreased male fertility.

Of course, correlation doesn't necessarily mean causation (and it would be hard to ethically truly *prove* causation of reduced male fertility in males), and there may be other environmental factors that coincide with increased estrogen (like obesity, processed foods, or anything associated mainly with the developed world), I find that to be much more worrying than environmental exposures of the mother.

I would "blame" the mother for decreased sperm count if it was caused by her smoking during pregnancy, but otherwise, what can you really do? Unless you want to cordon yourself off from modern society, there are certain environmental exposures that will take a lot of time and a lot of innovation to eliminate.

Frankly, until decreased sperm count *directly* starts resulting in fewer babies being born than people dying, I can't see anyone putting that much effort into it, and I really think we have more important issues to focus on.
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Don't you think the title is a bit misleading? Blaming mothers for environmental factors that are largely unavoidable is a little unfair. Mom's are hard enough on themselves as it is and tomorrow is Mother's Day for Pete's sake. How about we cut mom some slack and put the blame where it's due: toxins in our environment.
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Interesting. From an evolutionary persceptive, this function would reduce the number of damaged offspring in the general population, increasing the survivability of the species as a whole.

Thanks, Mom.
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