Dad's Problem Is Mom's Fault
Man is somewhat inferior to other mammals when it comes to sperm production. Humans just don't produce many sperm that are capable of making it all the way to that elusive target: the egg. According to the guidelines of the World Health Organization (WHO), only 5%-15% of human sperm can be classed as normal and these are only found in men who are young and healthy. Now compare these figures to the over 90% normal sperm produced by a ram, bull, or laboratory rat. Shocking, isn't it?
Men fall prey to a high rate of reproductive issues that range anywhere from undescended testicles all the way to impotence and cancer. The result of this is that more men are finding themselves incapable of producing children. Experts now posit that of the one in every seven couples diagnosed with infertility, male factor infertility is now the most common cause identified.
Almost two decades ago, Niels Skakkebaek informed a WHO conference that sperm counts had dropped to half their former level over the past half a century. In the 1940's typical sperm counts were over 100,000 sperm cells in every milliliter, but had since dropped to around 60,000 in every milliliter. Some studies found that 15%-20% of young males had sperm counts of less than 20,000 per milliliter, which is below normal levels. This is in contrast to a bull's count for viable sperm which reaches into the billions.
There was a fear that man would become incapable of reproduction within a few more generations, but recent studies have thankfully found that the falling sperm counts have leveled off. Skakkebaek had thought that the drop in viable sperm counts may have something to do with rising rates of reproductive problems such as cancer of the testicles. In any case, most experts agree that whatever the cause might be, male infertility likely begins in the womb.
It seems that the lifestyle of males is not at fault in the decline of viable sperm, though the lifestyles of their mothers are almost certainly the primary cause for male factor infertility. While men don't produce sperm until adolescence, the infrastructure for sperm production is put in place during the final trimester of gestation and just after birth. Anything that interferes with testicular development during gestation and the first six months in the life of a male will have everlasting consequences on his fertility.
Men whose moms were exposed during pregnancy to high levels of dioxins during a 1976 accident in Seveso, Italy had below normal sperm counts, while men exposed to dioxins as adults saw no appreciable affect on their fertility. Women who ate lots of beef during pregnancy had sons with low sperm counts due to the high levels of polycyclic aromatic hydrocarbons found in beef, but men who ate a lot of beef as adults sustained no damage to their fertility. Men whose mothers smoked in pregnancy displayed a dramatic lowering of their sperm counts—up to 40%--and this is probably irreversible, but when men smoke as adults, the reduction in sperm count is only around 15% and is reversible should he decide to quit smoking.
In other words guys, here's another thing you can blame on Mom: infertility.