Actually...
Snip
There have been a number of studies over the past 15-20 years (1, 2, 3, 4, 5, 6 and 10), which suggest that sperm counts in man are on the decline. Since these changes are recent and appear to have occurred internationally, it has been presumed that they reflect adverse effects of environmental or lifestyle factors on the male rather than, for example, genetic changes in susceptibility. If the decrease in sperm counts were to continue at the rate that it is then in a few years we will witness widespread male infertility. To date it remains unknown why this is happening and the available preventative measures, which can be taken to avoid a continuation of this trend, are not common knowledge.
Told you.