The concept that sperm counts have declined with time because of environmental and lifestyle impacts is not new, but has remained controversial. The present study is hugely impressive, and for numbers (26,600 men), dwarfs previous studies, giving it immense power.
The take-home message from the study is extremely simple: sperm number and sperm quality has declined progressively over the study period. This confirms that sperm counts have, or are, falling.
These findings have two implications: more couples will experience fertility problems; and the decrease in sperm counts demonstrates that something in our modern lifestyle, diet or environment (eg chemical exposures) is causing this, and it is getting progressively worse.
We still do not know which are the most important factors, but perhaps the most likely is a combination (“double whammy”) of changes such as a high fat diet combined with increased environmental chemical exposures.
In the UK this issue has never been viewed as a priority, perhaps because of doubts as to whether “falling sperm counts” was real. Now, there can be little doubt that it is real, so it is time for action. Doing nothing will ensure that couple fertility and average family size will decline below even its present low level and place ever greater strains on society.