On the Nature of Things | Forum

A meta-analysis published in the British Medical Journal determined that between 1938 and 1990, American men suffered a “genuine decline in semen quality”—results that suggest “an overall reduction in male fertility.”

After the federal Centers for Disease Control and Prevention began to include men in its National Survey of Family Growth, agency surveys, based on data collected between 2006 and 2010, concluded that 12 percent of American men between the ages of 25 and 44 suffered from some form of infertility. Some 10 percent used infertility services.