It was 16 years ago at about this time when I wrote my first blog. Ever. Top of mind at that time was my thinking that male infertility was not simply something that, coincidentally, happened to otherwise perfectly healthy men. Just a matter of “bad luck,” right? Nope. Reproductive competence is far too important to God or Darwin to fail from the whim of chance. I’ve never done this before but to quote myself back then, I stated that “infertility is a ‘window’ into men’s health. It reflects on the current health of men and reflects on their future health.” Fertility is a biomarker of health. Years later, to my surprise and glee, it appears that this has now become scientific fact.

Fertility as Biomarker

Agreeing with Einstein that “God doesn’t play dice with the universe,” especially when it comes to reproduction, my statement was based on several years of serious scientific discoveries that we made while I was a hard-charging professor at UCSF. First, we showed that severely infertile men had trouble repairing the genetic errors that routinely occur to DNA as we roll through our earthly existence, errors that in mice and man are known to lead to cancers later in life. Then, to substantiate this theory, we demonstrated that severely infertile men are more likely to have higher rates of testicular and prostate cancer with age. Other colleagues took this baton and went further to show that infertile men have a higher disease burden (e.g. more diseases) both at the time of infertility and later in life, have higher rates of cardiovascular disease later and possibly even shorter life expectancies than fertile men. And so, over the last decade and a half, the biomarker concept of male fertility as a window into overall health was introduced, tested, contested, labored and belabored, all to prove its truth. But the icing on the cake, the pièce de resistance, in this small corner of science was just published and really brought the whole home for me.

There’s a There There

In this trajectory of biomarker thought, the ultimate confirmation of relevance and truth would be to show that the best measure of fertility we have, the semen analysis, correlates with the best measure of overall health we have, longevity. To this end, a convincing study just released showed a dose dependent relationship between semen quality and life expectancy. And that, my friends, is something to really pay attention to.

Straight from the storied Righospitalet Hospital in Copenhagen Denmark, researchers showed that young men with normal semen quality lived almost 3 years longer (80.3 vs. 77.6) than men with poor semen quality. What lends serious credence to this work is that over 78,00 men were followed for up to 50 years (median 23 years), a task that is not possible in most health care systems worldwide. The believability factor increases even more whenever a “dose response” relationship is demonstrated between an exposure (fertility potential) and the outcome (longevity), which was also observed in the Danish study. So, there really is a there there!

Theory as Fact

We were put on this good earth to eat, sleep and reproduce. So, when reproduction fails it really must be for good reason. And that reason is health. This has been a theory of mine now for 2 decades. Simply stated, a “theory” is how we see the world. And “fact” is the way the world actually is. Although I have believed this to be true for decades, I now accept as scientific fact that a man’s fertility potential is a biomarker of both his current and future health.