Vagina -- The female organ of sexual intercourse; the birth canal.
Vaginismus -- A spasm of the muscles around the opening of the vagina, making penetration during sexual intercourse either impossible or very painful. Can be caused by physical or psychological conditions.
Vaginitis -- An inflammation of the vagina. Yeast, bacterial vaginosis, or trichomonas infections of the vagina. Frequent vaginitis may indicate the presence of pelvic adhesions and tubal blockage from other infections, such as chlamydia. Vaginitis may interfere with sperm penetration of the cervical mucus, and the symptoms may even interfere with the ability and desire to have intercourse.
Varicocele -- Varicose veins in the scrotum. The resulting swollen vessels surrounding the testicles create a pool of stagnant blood, which elevates the scrotal temperature. A major cause of male infertility.
Vas Deferens -- The pair of thick-walled tubes through which the sperm move from the epididymis to the ejaculatory duct in the prostate. These tubes are severed during a vasectomy performed for birth control.
Vasectomy -- The surgical separation of both vas deferens. A procedure used for birth control/sterilization.
Vasectomy Reversal -- Surgical repair of previous vasectomy in order to restore fertility.
Vasogram -- An X-ray examination of the vas deferens.
Venereal Disease -- Any infection that can be sexually transmitted, such as chlamydia, gonorrhea, ureaplasma, and syphilis. Many of these diseases will interfere with fertility and some will cause severe illness. See also PID.
Viable -- Capable of sustaining life. Often used to describe an early pregnancy in which a heartbeat has been seen.
Virus -- A microscopic infectious organism that reproduces inside living cells.
Viscosity -- The thickness of semen.
Vulva -- Female's external genitalia.