Infertility is the inability to become pregnant after one year of trying to conceive without the use of birth control, according to FamilyDoctor.org. The site adds that approximately 15 percent of couples experience this problem, with almost one-third of all cases due to male sterility. A variety of factors contribute to this, some of which may be treatable.
Morphology and Motility of Sperm
Morphology is the structure of the sperm, while motility is the amount sperm moves. For fertilization of an egg to take place, the shape must be correct and sperm must be able to move rapidly. If an impairment is evident in either, it hinders the ability of the sperm to reach and penetrate the egg.
Undescended Testicle
During fetal development, the testicles should descend from the abdomen into the scrotum. For some men, the testicles do not do this, exposing them to a higher internal body temperature. This can result in lower sperm production, according to MayoClinic.com.
Infections
MayoClinic.com points out that an infection may temporarily affect sperm motility. Sexually transmitted diseases, such as chlamydia and gonorrhea, are frequently linked with male sterility, according to MayoClinic.com. The scarring they cause blocks the sperm's movement. Viral infections such as the mumps tend to cause inflammation of the testicles and impair the production of sperm. Prostatitis---inflammation of the prostate---can also hinder the motility of sperm.
Hormonal Deficiencies
The University Of Maryland Medical Center explains that hormonal deficiencies affect the release of testosterone and other reproductive hormones. When testosterone levels are low, one result may be defective sperm production.
Hypogonadism is the name for a severe deficiency in GnRH, or gonadotropin-releasing hormone, the primary hormone responsible for the release of testosterone. It is rare and when it does occur, it is usually present at birth.
Lifestyle Factors
In some cases, a man's lifestyle causes sterility. Tobacco and illicit drug use, alcohol consumption and obesity are factors a man can control. Age is not controllable though, and as he approaches 35 years old, the quality of his sperm begins to decline. The older he becomes, the slower his sperm move.
