Sperm Abnormality:

Sperm can have an abnormal shape and movement that would create problems for fertilization. The shape and structure of a sperm is referred to as "sperm morphology". Obviously if the sperm have mobility problems they will have difficulty even reaching the egg. Any abnormal shape of the sperm also contributes to difficulty with mobility.

The absence of sperm in the testicles is extremely rare but it does occur and is a cause for infertility. Couples who are diagnosed with this as their cause for infertility have very little options, other than sperm donor or adoption.

Normally a man will produce approximately 20 million sperm per milliliter of semen. If the test reveals that a man has 10 million or fewer, that would be classified as having a low sperm count. There can be many reasons for a low sperm count. When a man has less than 5 million sperm per milliliter of semen, than genetic causes are considered.

Reasons for low sperm count:

Diseases like Varicocele, which prevents the testicle from cooling. When temperature is too high sperm cannot survive. Cryptorchidism or an undescended testicle occurs when one or both of the male testicles fail to descend from the abdomen into the scrotum during fetal development. This causes problems in sperm production because the sperm are exposed to higher body temperature in the abdomen.

Other causes of low sperm count are: disorders of the testicles or abnormal hypothalamus or pituitary glands. There is a disorder of the sex chromosomes that can cause abnormal development of the testicles which results in a lower than normal level of testosterone.

Males who contract certain infections can also have an adverse affect on their sperm count. Infections such as some sexually transmitted diseases like chlamydia or gonorrhea. Scarring happens during the course of these diseases that can cause block the passage of sperm. When males come down with the disease mumps past childhood, they can experience an inflammation of their testicles that may result in lower sperm counts or impaired sperm. Should the man's prostate, urethra or epididymis become inflamed this can cause motility problems with his sperm.

Delivery Problems:

Delivery problems are classified as when the man has difficulty getting the sperm from his penis into the woman's vagina.

Causes can be:

Sexual in nature

Problems with the ejaculation

A possible blockage in the epididymis or the ejaculatory ducts

Absense of the fluid part of the semen

A misplaced urinary opening, also known as the "hypospadias"

Anti-sperm antibodies (usually present in cases of men undergoing a reversal of a vasectomy.

Cystic fibrosis - men with this disease may not have a vasa deferentia or it may be blocked.

Health and Lifestyle Causes:

Emotional stress

Deficiencies in Vitamin C, Selenium, zinc or folate

Obesity

Cancer and the treatment for this disease

Alcohol and drugs

Severe injury or having major surgery to the male reproductive organ

Other diseases that can contribute to male infertility are:

Anemia

Diabetes

Cushing's syndrome

Having a heart attack

HIV/AIDS

Kidney or Liver failure

Age:

Just like in women there is a decline in fertility with men after age 35. Men however, have a more gradual decline in fertility than women do.