1. Evidence for decreasing quality of semen during past 50 years;Carlsen;BMJ,1992
2. Is human fecundity declining-and does occupational exposures play a role in such a decline if it exists?;Olsen;Scand J Work Environ Health,1994
3. Decline in semen quality among fertile men in Paris during the past 20 years;Auger;N Engl J Med,1995
4. Deterioration of sperm quality in young Belgian men during recent decades;Van Waeleghem;Hum Reprod,1994
5. Evidence of deteriorating semen quality in the United Kingdom: birth cohort study in 577 men in Scotland over 11 years;Irvine;BMJ,1996