Some researchers have pointed to environmental toxins, stress, and obesity as contributing factors.
Sperm count among men from North America, Europe, Australia, and New Zealand dropped by nearly 60 percent between 1973 and 2011, according to a recent study published in an Oxford University journal. The findings by the international research team — who examined semen samples from 42,935 men from 50 countries — reinforce concerns that Western male health may be at risk.
Although the research did not focus on the cause of these declines, study coauthor Shanna Swan, PhD, a professor of environmental medicine and public health at New York’s Icahn School of Medicine at Mount Sinai, referred to existing research that cited several factors: exposure to cigarette smoke, alcohol, and chemicals while in utero; environmental toxins; and stress and obesity.
Researchers found no significant decline in sperm count among men from Asia, Africa, and South America.
In past studies, Swan has noted that Western countries began using chemicals like phthalates (plastic-softening agents that are linked to male hormone disruption) much earlier than non-Western countries.
For more on infertility issues, see “5 Causes of Unexplained Infertility.”