As we all know, it takes "two to tango".

An interesting article on documented causes of male infertility issues - low sperm count, vitality, motility etc.

Some suggestions as well.

Link: http://articles.mercola.com/sites/ar...ng-blanks.aspx

Tetraethyl-lead seems to be the largest sperm-killer by far, there are studies that seem to suggest that the TEL used in motor-cars up untill 2000 could have wiped us out as a species. Since the ban in 2000 sperm-count has been on the rise again.
However AvGas is still leaded, so watch after your junk around airports