Structural issues
Obstruction can stop the passage of spermatozoa meaning the semen is sperm-free. A blockage can occur due to a congenital disorder (eg prostatic cysts, a missing vas deferens, or an obstruction in the epididymis) or be acquired after surgery (eg a vasectomy, scrotal or bladder surgery, or hernia repair) or infection.5
A varicocele, an enlargement of the veins in the scrotum, is associated with reduced male fertility, but the mechanism is unclear. Surgery to remove the varicocele can improve semen quality.
Hypogonadism in males, with reduced spermatogenesis and/or testosterone production can result from:
- testicular failure;
- insufficient secretion of gonadotropin-releasing hormone (GnRH), gonadotropin (follicle stimulating hormone [FSH], and/or luteinizing hormone [LH]);
- an insensitivity to androgens.
Erectile dysfunction and ejaculation disorders may arise due to psychological factors, hypogonadism, vascular or metabolic diseases such as diabetes, and spinal cord injury or disease.