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Male Reproduction

The Male Reproductive System and Disorders

A variety of conditions affect male reproduction with a number of these male reproductive disorders directly or partially associated with the endocrine system. Male reproductive disorders caused by chromosomal abnormalities, such as Klinefelter’s syndrome, or hormonal disorders including Kallmann syndrome, can result in low testosterone (hypogonadism), erectile dysfunction and decreased sperm production.

Symptoms of Conditions that Affect Male Reproduction

There are many male reproductive disorders that affect male reproduction with a wide variety of symptoms. Male reproductive disorders that affect the endocrine system typically result in symptoms including:

  • Low testerosterone (hypogonadism)
  • Erectile dysfunction
  • Decreased sperm production
  • Reduced facial and body hair
  • Infertility
  • Breast enlargement (gynecomastia)

Causes of Conditions Affecting Male Reproduction

Problems with the production and maturation of sperm are the most common causes of male infertility. Sperm may be immature, abnormally shaped, or unable to move properly. Additionally, normal sperm may be produced in abnormally low numbers (oligospermia) or not at all (azoospermia). This problem may be caused by several disorders (including male reproductive disorders) such as:

  • Infectious diseases or inflammatory conditions such as the mumps virus
  • Liver disease, renal disease, or treatment for seizure disorders
  • Endocrine or hormonal disorders such as Kallmann syndrome or a pituitary problem
  • Immunological disorders in which some men produce antibodies to their own sperm
  • Environmental and lifestyle factors
  • Genetic diseases and male reproductive disorders (most are associated with sperm abnormalities, either directly or indirectly):
    • Cystic fibrosis — an inherited condition that typically involves the lungs and pancreas, but can present also as a cause of infertility with or without mild sinus problems. Most men who have cystic fibrosis have obstructive azoospermia, because they were born without a vas deferens resulting in male infertility.
    • Noonan syndrome — an inherited condition which can occur in either males or females. In males, this syndrome can cause abnormal gonadal (testicular) function.
    • Myotonic dystrophy — an inherited condition with progressive multi-system involvement, resulting in infertility (underdeveloped testes and abnormal sperm production), in some cases.
    • Hemochromatosis — an inherited condition affecting iron storage. 80% of men with hemochromatosis have testicular dysfunction.
    • Sickle cell disease — an inherited condition affecting the normal production of hemoglobin.
    • Sex reversal syndrome — a male who has the sex chromosomes of a genetic female (XX, instead of XY), resulting in azoospermia and other characteristics.
    • Androgen receptor gene mutations — an inherited condition in which a man is genetically male (46,XY), but has infertility due to a defect in receptors for testosterone.
    • Chromosomal abnormalities — men with an extra X sex chromosome, known as Klinefelter syndrome, often do not produce sperm or produce very low quantities of sperm.
    • Chromosome rearrangements — in some persons, there are the usual number of chromosomes (46) in the nucleus (center) of cells, but rearrangements in the chromosome material, where a piece of a chromosome has exchanged places with another, has taken place; men with either azoospermia or oligospermia have a higher frequency of chromosome rearrangements than one would found in the general population.
    • Deletions in the Y chromosome — in some persons, there are the usual number of chromosomes (46) in the body cells, but small sections of the Y chromosome are missing or deleted; a small percentage of men with either azoospermia or oligospermia have deletions in the Y chromosome.

Note that men who have genetic male reproductive disorders or issues with the male reproduction system resulting with infertility (such as a deletion in the Y chromosome), can pass this genetic defect on to male children.

Additionally, issues with male reproduction can be traced to:

Anatomical abnormalities — Obstructions of the genital tract can cause infertility by partially or totally blocking the flow of seminal fluid. Some of these abnormalities may be of congenital (present at birth) origin or the result of a genetic defect. Male reproductive disorders could have occurred due to infection or inflammation of the urogenital tract, surgery that left scar tissue in the genital tract, or the presence of varicose veins in the scrotum (scrotal varicoceles).

Immotile cilia syndrome — In this male reproductive disorder, the sperm count is normal but the spermatozoa are non-motile such as in Kartagener's syndrome (an inherited disorder).

Mitochondrial deletions — Mitochondria are structures in the cell responsible for energy production. These structures contain their own set of genes, separate from the normal chromosome set contained in the nucleus. Deletion or alteration of these structures can affect a person's health and/or fertility, ultimately affecting male reproduction.

Other factors — Other factors contributing to male reproductive disorders may arise from the defective delivery of sperm into the female genital tract, which could be caused by impotence or premature ejaculation.