Infertility
Male Infertility: Etiology and Diagnosis
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In the United States alone, approximately fifteen percent of all couples have difficulty conceiving a child. Male infertility is implicated in about one third of these cases. Moreover, current estimates suggest that about six percent of males between the ages of fifteen and fifty are infertile. Researchers agree that male infertility results from two main causes, namely, decreased sperm production and/or defects in the quality of the sperm produced.
From the quantitative standpoint, decreased sperm production accounts for about ninety percent of all cases of male infertility. Although it only takes one sperm to fertilize an egg, the average ejaculate of a healthy man usually contains about two hundred million sperm. However, because of natural barriers in the female reproductive system, only about forty sperm will every reach the environs of an egg. If pregnancy is to be achieved, therefore, it is crucial for the ejaculate to contain the requisite number of sperm. Interestingly, studies have shown that the total sperm count of the general male population has been declining steadily during the past seventy years. This downward trend in sperm count has led to speculation that environmental, dietary, and lifestyle issues may be interfering with a man's ability to manufacture sperm. Although still controversial, a great deal of evidence is being garnered to substantiate this claim.
Qualitatively speaking, a high sperm count means little if the percentage of healthy sperm is not also high. Researchers are rapidly learning that sperm quality is perhaps an even more important cause of male infertility than sperm quantity. Sperm quality is linked to sperm morphology and motility. Whenever the majority of sperm are abnormally shaped or are entirely or relatively nonmotile, a man can be infertile despite having a normal sperm concentration. Environmental toxins, prescription drugs, and exposure to radiation have been identified as the main causes of damaged sperm.
Laboratory analysis of sperm concentration and quality remains the preferred method of diagnosing male infertility, although more sophisticated tests aimed at measuring the sperm's penetrative power and detecting the possible presence of antisperm antibodies are now available.
