Smoking is bad for men’s fertility. Not unexpected, you might add, since 1000 smokers die each day around the world from smoking related diseases. But what else is new? A lot. And this matters because 25 million men in America smoke. Along with 21 million women. Any other condition this common would certainly be considered a frightening epidemic.
Although we always suspected that smoking impairs sperm quality and quantity, two papers published this week shed light on ways in which this could occur. Mechanistic in design, this research approached the problem from different angles and each made unique observations.
One study compared the integrity of sperm DNA in smokers and nonsmokers. As background, realize that a sperm’s job is to deliver a neatly packaged DNA payload to the egg during what is called fertilization. The egg then molecularly “undresses” the sperm DNA and decides over the next day or two whether that genetic payload is of high enough quality or integrity to proceed down the pathway toward becoming an embryo and then a fetus. If not, an executive decision is made by the fertilized egg to stop dividing and call it a day. Protamines are molecules that protect the DNA in sperm so that it remains neatly packaged, and in this study, the smoker’s sperm had significantly disrupted protamine protein levels compared to the sperm of non-smokers. That explains the sperm quality problem: smoking poisons sperm.
A second study took a different look at smoking and infertility. It assessed the impact of maternal smoking habits during early pregnancy on male fetal development. Based on the examination of miscarriages, they found that number of testicular stem cells that are destined to become sperm later in life in the male fetuses of mothers who smoked was half of that of their nonsmoking counterparts. And this observation held true when other social drugs like caffeine and alcohol were taken into account. Fewer stem cells in the developing testicle could mean fewer sperm and a higher risk of infertility in adult sons. This might explain a sperm quantity issue in some infertile men–in men who don’t even have to smoke to have the problem.
So ditch the coffin nails and let your life burn bright in other ways. There are many ways to have your breath taken away. As Woody Allen said: “Remember, if you smoke after sex, then you are doing it too fast.”