Has fertility declined in recent decades?
OBJECTIVE
Increasing use of infertility treatment and a decline in demographic fertility in some countries have raised concern whether human fecundity is declining or has declined over time. A dramatic decline in semen quality over the past half-century has been proposed and widely discussed, but none of the existing studies provide data good enough for coming to any firm conclusion.


RESULTS
Results from 19 articles published during the last 5 years on semen quality and fecundity, covering data from the Nordic countries since the year 2000, do not indicate an ongoing decline in fertility.


CONCLUSIONS
We will probably never know, whether semen quality and fecundity has declined over time, but we may be able to monitor biological fecundity and semen quality over time from now on. There are both research initiatives and interest from official channels that could provide more funding for infertility research.
Department of Epidemiology, Institute of Public Health, University of Aarhus, Aarhus, Denmark.
Jørn
J
Olsen
Jin Liang
JL
Zhu
Cecilia H
CH
Ramlau-Hansen
D005260:Female; D006801:Humans; D007246:Infertility / Q000453:epidemiology*; D008297:Male; D012537:Scandinavian and Nordic Countries / Q000453:epidemiology; D055101:Semen Analysis