Semen Analysis: The quality of SEMEN, an indicator of male fertility, can be determined by semen volume, pH, sperm concentration (SPERM COUNT), total sperm number, sperm viability, sperm vigor (SPERM MOTILITY), normal sperm morphology, ACROSOME integrity, and the concentration of WHITE BLOOD CELLS.Semen: The thick, yellowish-white, viscid fluid secretion of male reproductive organs discharged upon ejaculation. In addition to reproductive organ secretions, it contains SPERMATOZOA and their nutrient plasma.Sperm Count: A count of SPERM in the ejaculum, expressed as number per milliliter.Sperm Motility: Movement characteristics of SPERMATOZOA in a fresh specimen. It is measured as the percentage of sperms that are moving, and as the percentage of sperms with productive flagellar motion such as rapid, linear, and forward progression.Infertility, Male: The inability of the male to effect FERTILIZATION of an OVUM after a specified period of unprotected intercourse. Male sterility is permanent infertility.Andrology: A scientific or medical discipline concerning the study of male reproductive biology, diseases of the male genital organs, and male infertility. Major areas of interest include ENDOCRINOLOGY; SPERMATOGENESIS; semen analysis; FERTILIZATION; CONTRACEPTION; and CRYOPRESERVATION.Spermatozoa: Mature male germ cells derived from SPERMATIDS. As spermatids move toward the lumen of the SEMINIFEROUS TUBULES, they undergo extensive structural changes including the loss of cytoplasm, condensation of CHROMATIN into the SPERM HEAD, formation of the ACROSOME cap, the SPERM MIDPIECE and the SPERM TAIL that provides motility.Semen Preservation: The process by which semen is kept viable outside of the organism from which it was derived (i.e., kept from decay by means of a chemical agent, cooling, or a fluid substitute that mimics the natural state within the organism).Varicocele: A condition characterized by the dilated tortuous veins of the SPERMATIC CORD with a marked left-sided predominance. Adverse effect on male fertility occurs when varicocele leads to an increased scrotal (and testicular) temperature and reduced testicular volume.Manuals as Topic: Books designed to give factual information or instructions.Oligospermia: A condition of suboptimal concentration of SPERMATOZOA in the ejaculated SEMEN to ensure successful FERTILIZATION of an OVUM. In humans, oligospermia is defined as a sperm count below 20 million per milliliter semen.Ejaculation: The emission of SEMEN to the exterior, resulting from the contraction of muscles surrounding the male internal urogenital ducts.Vasectomy: Surgical removal of the ductus deferens, or a portion of it. It is done in association with prostatectomy, or to induce infertility. (Dorland, 28th ed)Asthenozoospermia: A condition in which the percentage of progressively motile sperm is abnormally low. In men, it is defined as Sperm Banks: Centers for acquiring and storing semen.Azoospermia: A condition of having no sperm present in the ejaculate (SEMEN).Fertility: The capacity to conceive or to induce conception. It may refer to either the male or female.Clinical Laboratory Services: Organized services provided by MEDICAL LABORATORY PERSONNEL for the purpose of carrying out CLINICAL LABORATORY TECHNIQUES used for the diagnosis, treatment, and prevention of disease.Chromomycin A3: Glycosidic antibiotic from Streptomyces griseus used as a fluorescent stain of DNA and as an antineoplastic agent.Acrosome Reaction: Changes that occur to liberate the enzymes of the ACROSOME of a sperm (SPERMATOZOA). Acrosome reaction allows the sperm to penetrate the ZONA PELLUCIDA and enter the OVUM during FERTILIZATION.Cryopreservation: Preservation of cells, tissues, organs, or embryos by freezing. In histological preparations, cryopreservation or cryofixation is used to maintain the existing form, structure, and chemical composition of all the constituent elements of the specimens.Scrotum: A cutaneous pouch of skin containing the testicles and spermatic cords.Embryology: The study of the development of an organism during the embryonic and fetal stages of life.Spermatogenesis: The process of germ cell development in the male from the primordial germ cells, through SPERMATOGONIA; SPERMATOCYTES; SPERMATIDS; to the mature haploid SPERMATOZOA.Insemination, Artificial: Artificial introduction of SEMEN or SPERMATOZOA into the VAGINA to facilitate FERTILIZATION.Testis: The male gonad containing two functional parts: the SEMINIFEROUS TUBULES for the production and transport of male germ cells (SPERMATOGENESIS) and the interstitial compartment containing LEYDIG CELLS that produce ANDROGENS.Sperm Head: The anterior portion of the spermatozoon (SPERMATOZOA) that contains mainly the nucleus with highly compact CHROMATIN material.Spermatocele: A cystic dilation of the EPIDIDYMIS, usually in the head portion (caput epididymis). The cyst fluid contains dead SPERMATOZOA and can be easily differentiated from TESTICULAR HYDROCELE and other testicular lesions.Sperm-Ovum Interactions: Interactive processes between the oocyte (OVUM) and the sperm (SPERMATOZOA) including sperm adhesion, ACROSOME REACTION, sperm penetration of the ZONA PELLUCIDA, and events leading to FERTILIZATION.Sexual Abstinence: Refraining from SEXUAL INTERCOURSE.Infertility: Inability to reproduce after a specified period of unprotected intercourse. Reproductive sterility is permanent infertility.World Health Organization: A specialized agency of the United Nations designed as a coordinating authority on international health work; its aim is to promote the attainment of the highest possible level of health by all peoples.Quality Control: A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required. (Random House Unabridged Dictionary, 2d ed)Seminal Plasma Proteins: Proteins found in SEMEN. Major seminal plasma proteins are secretory proteins from the male sex accessory glands, such as the SEMINAL VESICLES and the PROSTATE. They include the seminal vesicle-specific antigen, an ejaculate clotting protein; and the PROSTATE-SPECIFIC ANTIGEN, a protease and an esterase.Fertility Preservation: A method of providing future reproductive opportunities before a medical treatment with known risk of loss of fertility. Typically reproductive organs or tissues (e.g., sperm, egg, embryos and ovarian or testicular tissues) are cryopreserved for future use before the medical treatment (e.g., chemotherapy, radiation) begins.Reproductive Techniques, Assisted: Clinical and laboratory techniques used to enhance fertility in humans and animals.Insemination, Artificial, Homologous: Human artificial insemination in which the husband's semen is used.Pregnancy Rate: The ratio of the number of conceptions (CONCEPTION) including LIVE BIRTH; STILLBIRTH; and fetal losses, to the mean number of females of reproductive age in a population during a set time period.Chromosomes, Human, Y: The human male sex chromosome, being the differential sex chromosome carried by half the male gametes and none of the female gametes in humans.Fertilization in Vitro: An assisted reproductive technique that includes the direct handling and manipulation of oocytes and sperm to achieve fertilization in vitro.Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.Clinical Laboratory Techniques: Techniques used to carry out clinical investigative procedures in the diagnosis and therapy of disease.Testosterone: A potent androgenic steroid and major product secreted by the LEYDIG CELLS of the TESTIS. Its production is stimulated by LUTEINIZING HORMONE from the PITUITARY GLAND. In turn, testosterone exerts feedback control of the pituitary LH and FSH secretion. Depending on the tissues, testosterone can be further converted to DIHYDROTESTOSTERONE or ESTRADIOL.Fertilization: The fusion of a spermatozoon (SPERMATOZOA) with an OVUM thus resulting in the formation of a ZYGOTE.Follicle Stimulating Hormone: A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Follicle-stimulating hormone stimulates GAMETOGENESIS and the supporting cells such as the ovarian GRANULOSA CELLS, the testicular SERTOLI CELLS, and LEYDIG CELLS. FSH consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH, and FSH), but the beta subunit is unique and confers its biological specificity.Zona Pellucida: A tough transparent membrane surrounding the OVUM. It is penetrated by the sperm during FERTILIZATION.Sperm Injections, Intracytoplasmic: An assisted fertilization technique consisting of the microinjection of a single viable sperm into an extracted ovum. It is used principally to overcome low sperm count, low sperm motility, inability of sperm to penetrate the egg, or other conditions related to male infertility (INFERTILITY, MALE).Infertility, Female: Diminished or absent ability of a female to achieve conception.Reference Values: The range or frequency distribution of a measurement in a population (of organisms, organs or things) that has not been selected for the presence of disease or abnormality.DNA Fragmentation: Splitting the DNA into shorter pieces by endonucleolytic DNA CLEAVAGE at multiple sites. It includes the internucleosomal DNA fragmentation, which along with chromatin condensation, are considered to be the hallmarks of APOPTOSIS.Luteinizing Hormone: A major gonadotropin secreted by the adenohypophysis (PITUITARY GLAND, ANTERIOR). Luteinizing hormone regulates steroid production by the interstitial cells of the TESTIS and the OVARY. The preovulatory LUTEINIZING HORMONE surge in females induces OVULATION, and subsequent LUTEINIZATION of the follicle. LUTEINIZING HORMONE consists of two noncovalently linked subunits, alpha and beta. Within a species, the alpha subunit is common in the three pituitary glycoprotein hormones (TSH, LH and FSH), but the beta subunit is unique and confers its biological specificity.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.