Tobacco And Sperm
Although research and clinical trials have indicated that smoking tobacco in any form (and indeed chewing tobacco) can reduce a man's fertility, it's not certain that smoking on its own can cause a man to become completely infertile. It seems more likely that smoking can do a certain degree of damage to the quality and quantity of a man's sperm cells. Therefore, if his fertility is already compromised in some other way (for example, a defect in the testicles), smoking may be the factor that pushes his fertility down to zero.
Similarly, alcohol also damages sperm production - but smoking and drinking alcohol together is the real lethal combination. Medical evidence proves that a man who drinks and smokes heavily is likely to have a lower sperm count than a man who only smokes or only drinks. Having said that, the only way to make sure that neither of these habits impacts on a man's fertility is for him to abstain from them completely, at least while he and his partner are trying to conceive.
Quantity, Morphology, Motility
For the sperm cells in a man's semen to be healthy and stand a good chance of fertilizing an egg, there needs to be a certain quantity (20 million or more) of sperm cells in each milliliter of his semen. The sperm cells also need to have oval-shaped heads and one long, strong tail that they use, first of all to propel themselves through the woman's uterus and into the fallopian tubes, and secondly to push their way through an egg's outer shell into its cytoplasm - where fertilization takes place.
The chemicals in tobacco cause some men to develop malformed, slow moving sperm, with tails that are not the right shape for adequate forward propulsion. Human sperm cells have nicotine receptors, just like all the other cells in the human body. Therefore nicotine consumption can interfere with the normal functioning of these cells.
Previous studies have found that smoking can decrease sperm concentration by as much as 23%, and reduce motility by up to 13%.
But that's not all. Some medical experts believe that it will eventually be proven that smoking can actually damage the DNA of a man's sperm cells. If this is in fact the case, it means that men who smoke are possibly getting their wives or girlfriends pregnant with genetically faulty sperm - this may be causing developmental problems for the children born of these pregnancies. Further research is currently underway in this area.
Last but certainly not least is the fact that heavy smoking can cause impotence. Smoking damages the blood vessels. Since healthy, strong blood vessels are essential for maintaining an erection, a man who smokes a lot, for a number of years, may have difficulty having sexual intercourse, which will obviously have a negative influence on his fertility.
Men who want to become fathers should seriously consider quitting smoking, whether or not they are finding it difficult to get their partners pregnant. Smoking may shorten life span, thereby reducing the years that a man will spend with his family. Passive smoking (i.e. breathing in someone else's smoke) is harmful to children and, possibly, to unborn children in the womb.