As a couple finishes its business, millions of sperm begin theirs: rushing toward an egg to fertilize it. But these days, scientists say, an increasing proportion of sperm — now about 90 percent in a typical young man — are misshapen, sometimes with two heads or two tails.
Even when properly shaped, today’s sperm are often pathetic swimmers, veering like drunks or paddling crazily in circles. Sperm counts also appear to have dropped sharply in the last 75 years, in ways that affect our ability to reproduce.
Human and animal studies suggest that a crucial culprit is a common class of chemical called endocrine disruptors, found in plastics, cosmetics, couches, pesticides and countless other products.
And so are men and boys. Apparently related to the problem of declining semen quality is an increase in testicular cancer in many countries; in undescended testicles; and in a congenital malformation of the penis called hypospadias (in which the urethra exits the side or base of the penis instead of the tip). These problems are often found together and are labeled testicular dysgenesis syndrome.
http://www.nytimes.com/2017/03/11/opini ... ouble.html