including decreased sperm motility and decreased sperm count. These studies suggest that environmental factors that influence fertility can be felt for generations even without changing the DNA. Post-testicular causes Post-testicular factors decrease male fertility due to conditions that affect the male genital system after testicular sperm production and include defects of the genital tract as well as problems in ejaculation: Vas deferens obstruction Lack of Vas deferens, often related to genetic markers for cystic fibrosis Infection, e.g. prostatitis, male accessory gland infection Retrograde ejaculation Ejaculatory duct obstruction Hypospadias Impotence Diagnostic evaluations The diagnosis of infertility begins with a medical history and physical exam by a physician, physician assistant, or nurse practitioner. Typically two separate semen analyses will be required. The provider may order blood tests to look for hormone imbalances, medical conditions, or genetic issues. Medical history The history should include prior testicular or penile insults (torsion, cryptorchidism, trauma), infections (mumps orchitis, epididymitis), environmental factors, excessive heat, radiation, medications, and drug use (anabolic steroids, selective serotonin reuptake inhibitors, alcohol, smoking). Sexual habits, frequency and timing of intercourse, use of lubricants, and each partner's previous fertility experiences are important. Loss of libido and headaches or visual disturbances may indicate a pituitary tumor. The past medical or surgical history may reveal thyroid or liver disease (abnormalities of spermatogenesis), diabetic neuropathy (retrograde ejaculation), radical pelvic or retroperitoneal surgery (absent seminal emission secondary to sympathetic nerve injury), or hernia repair (damage to the vas deferens or testicular blood supply). A family history may reveal genetic problems. Physical examination Usually, the patient disrobes completely and puts on a gown. The physician, physician assistant, or nurse practitioner will perform a thorough examination of the penis, scrotum, testicles, I vas deferens, spermatic cords, ejaculatory ducts, urethra, urinary bladder, anus and rectum. An orchidometer can measure testicular volume, which in turn is tightly associated with both sperm and hormonal parameters. A physical exam of the scrotum can reveal a varicocele, but the impact of detecting and surgically correct a varicocele on sperm parameters or overall male fertility is debated. Sperm sample Semen sample obtaining Semen sample obtaining is the first step in spermiogram. The optimal sexual abstinence for semen sample obtaining is of 2–7 days. The first way to obtain the semen sample is through masturbation, and the best place to obtain it is in the same clinic, as this way temperature changes during transport can be avoided,