Why it matters: Sperm densities in men across the Western world have fallen rapidly since the early 1970s. Some scientists have suspected that synthetics chemicals that disrupt the body's hormonal system have contributed to the decline, though the precise causes are not fully known.
- The low concentrations may have contributed to a global decline in fertility rate, though rates are influenced by numerous social and biological factors.
- Beyond affecting fertility, low sperm concentrations have also been associated with increased health risks, including higher rates of testicular cancer.
