How will smoking affect your legacy? Studying the effects on male fertility.

It’s long been known that women who smoke while pregnant are at a higher risk for health problems, including certain birth defects, premature birth, and even infant death.According to the Centers for Disease Control and Prevention, smoking also makes it more difficult for a woman to conceive; those who choose to smoke anyway run a greater risk of having a miscarriage than those who don’t.

And recent research on laboratory mice suggests that smoking while pregnant could harm the fertility of offspring.

Study author and Professor Eileen McLaughlin, co-director of the Priority Research Centre in Chemical Biology at the University of Newcastle, Australia, told the Telegraph newspaper, "Our results show that male pups of ‘smoking’ mothers have fewer sperm, which swim poorly, are abnormally shaped and fail to bind to eggs during in vitro fertilisation studies. Consequently, when these pups reach adulthood they are sub fertile or infertile.”

But what about the effects on fertility in men who smoke?

According to an April 2016 meta-analysis published in the journal European Urology, smoking is associated with decreased sperm count, poor sperm shape, and impaired sperm swimming ability. The analysis, which spanned 20 studies and slightly more than 5,000 men from all over Europe, also found that, compared to light smokers, the detrimental effects of smoking on sperm health was more intense in moderate to heavy smokers.

Here’s a troubling kicker to all of that, though: Male smoking is also connected to decreased IVF rates and, potentially, increased occurrences of miscarriages. Plus, secondhand smoke (the effects of smoke on a nearby non-smoker) can have consequences for a woman’s fertility.

One study indicated that secondhand smoke cut down on the number of eggs harvested in an IVF cycle by 46 percent.

That’s right. Lighting up doesn’t just affecting your own fertility, but that of your partner and likely your children, as well.

Let’s take a closer look at exactly how smoking affects sperm and semen quality:

  • Sperm morphology: This refers to the sperm’s shape. Abnormally shaped sperm might not swim decently enough to reach the egg. And even if they do, they might not have the power to fertilize the egg. Males who smoke have less healthy shaped sperm than men who don’t.
  • Sperm motility: Researchers determined that, in men who smoke, there’s a 13 percent decrease in motility, or the ability of a sperm to swim. And if the swimmers can’t make that final touch to the wall, the egg can’t be fertilized.
  • Sperm DNA: Studies have determined that men who smoke have sperm with greater DNA fragmentation. This could lead to problems with embryo development, fertilization, increased miscarriage rates, and embryo implantation.
  • Sperm concentration: Studies have shown that men who smoke have a 23 percent decrease in sperm concentration, which translates to the number of sperm present in a measured amount of semen.

To be sure, there’s still some debate as to whether decreases in sperm quality can cause infertility in men – at least, not all by themselves. However, men at the cusp of infertility could push themselves squarely into that realm were they to take up or continue smoking. And there’s no evidence suggesting that continuing to smoke will improve a man’s chances of success when it comes to fertility treatments.

The previously quoted meta-analysis also covered the area of the potential impact of paternal smoking on offspring. While there was no direct connection between a smoking father and his child’s fertility, researchers did discover a rise in birth defects among the children of men who smoke. There was also an increased risk of cancer, which could be attributable to damage to sperm DNA.

In the published conclusion of the meta-analysis, the researchers write, “Our results suggest that cigarette smoking has an overall negative effect on semen parameters.”

Can’t get much clearer than that, say what anyone might about a supposedly harmless puff here and there. And if the risks are indeed generational, there’s no point increasing your exposure when you have the safer, pre-emptive option of preserving your assets now. Your children and partner will someday thank you both for that choice. And as far as your legacy goes - so might your grandchildren

Khaled Kteily