The semen analysis is the primary test used in the evaluation of male infertility. It is usually the first evaluation for the male investigating infertility with his spouse and can reveal information about the ability of the sperm to reach the site of fertilization. The major parameters of the semen analysis include the sperm concentration, progressively motile sperm count and sperm morphology. There may be many reasons a male has fertility difficulties: a varicocele (like a varicose vein in the testes); too high or too low levels of hormones, lack of longevity for the sperm; anti-sperm antibodies (often due to damage with the blood/testis barrier); and genetic factors.