TY - JOUR AU - Merzenich, Hiltrud AU - Zeeb, Hajo AU - Blettner, Maria PY - 2010 DA - 2010/01/19 TI - Decreasing sperm quality: a global problem? JO - BMC Public Health SP - 24 VL - 10 IS - 1 AB - Carlsen and coworkers (1992) reviewed 61 heterogeneous observational studies on semen quality published between 1938 and 1990. This review indicates that mean sperm density decreased significantly between 1940 and 1990. An extended meta-analysis with 101 studies confirmed a decline in sperm density for the period from 1934 to 1996 (2000). The key message of the meta-analyses is that sperm counts have decreased globally by about 50% over the past decades. This assessment has been questioned. SN - 1471-2458 UR - https://doi.org/10.1186/1471-2458-10-24 DO - 10.1186/1471-2458-10-24 ID - Merzenich2010 ER -