Out of all things that are bad for the health of your sperm and future fertility, smoking is pretty high on the list. The worst thing is that not only can smoking potentially make you infertile, but it also increases your chances of getting a lot of different types of cancers. There are different mechanisms in place that causes the damage to your sperm by smoking, but what is important to note is that if quit smoking early on, some of this damage is reversible.
Few people know that smoking not only releases a lot of free radicals in your body that can damage your lungs and surrounding tissues, but it can also have a very strong, negative effect on the quality of the male sperm.
Every human's sperm carries two different proteins - called Protamine 1 and Protamine 2. These are tiny, highly charged proteins, and nature keeps them in a tight 1-to-1 balance. What smoking does is break this balance, making smoker carry less Protamine 2 in their sperm.
Over 20 different studies have been done in recent years to analyze the correlation between smoking and infertility. Pretty much all studies came to the same conclusion - if you want to be a father, you should probably stop smoking as soon as possible.
"Motility" is the word doctors and scientists use to describe the way sperm "swims." The studies on smokers show that not only do they have a lower amount of sperm count but that they also have reduced sperm motility - meaning their sperm doesn't "swim" as well as it should.
Among the other things the studies have found, is that smoking can even worsen infertility problems in men that are genetically prone to infertility, and the symptoms were far worse in the medium and heavy smokers (in comparison to light smokers).
Men's sperm can get so much damaged from smoking, that in some cases even IVF (In Vitro Fertilization) can be impossible due to the sperm not being able to move at all. In those couples, to only way to have children is by adoption.
In couples where the man was a heavy smoker, even when they were finally able to conceive a child, the woman still carried a larger chance of having a miscarriage. This fact alone should be enough to convince all future fathers to stop smoking.
In one study, where they analyzed the sperm concentrations (that's the density of the sperm) in over 5,000 men, smokers had a 23 percent decreased amount of sperm in comparison to men that haven't smoked for a long period of time.
Sperm morphology is a type of science that refers to the sperm's overall shape and size. What the study that was done on 5,000 men concluded was that smokers even had an inferior shape and size to their sperm, in comparison to non-smokers.
This should not come as a surprise, as smoking even damages the DNA of the smoker, but the sperm from men that smoked for a long period of time even had increased DNA fragmentation. This is another way of saying that the sperm's DNA was damaged.
What most of these studies show is that while smoking decreases the fertility, that just means that those men are going to have to "try" to conceive for a longer period. Complete infertility can occur in men who are borderline infertile before they began smoking.
Some guys try to turn to vaping or smoking "e-cigarettes" in a bid to improve their health. While vaping is far better for your health than smoking real cigarettes, these have their cons as well - one amongst them is that some of that e-cigarettes have been known to literally explode.
Another aspect researched looked at, is whether paternal smoking would lead to eventual infertility problems in his children. The studies, although not yet fully concluded, show that this does not seem to be the case - so the kids should not be sterile due to their father's smoking habit.
While paternal smoking was not indicated in reduced fertility in the offspring, there are a few studies that have shown that when the mother is a heavy smoker, there is an increased chance that her sons will have decreased fertility.
The conclusion of all of these studies is that even when a smoker can conceive a child, given that smoker's DNA is always going to be more damaged than non-smokers, they will always carry a higher chance of having children with a birth defect.