Gonad#Disease

{{Main|Evolution of sexual reproduction}}

It is hard to find a common origin for gonads, but gonads most likely evolved independently several times.{{Cite book|last=Schmidt-Rhaesa|first=Andreas |chapter=13. Reproductive organs |chapter-url={{GBurl|iiwTDAAAQBAJ|p=252}} |title=The Evolution of Organ Systems|date=2007-08-30|publisher=Oxford University Press|isbn=978-0-19-856668-7 |oclc=190852859 |pages=252 |quote=The diversity of modes in which gonads are formed makes it hard to substantiate a common origin of gonads. It appears to be more likely that gonads evolved independantly several times.}}

The gonads are controlled by luteinizing hormone (LH) and follicle-stimulating hormone (FSH), produced and secreted by gonadotropes or gonadotrophins in the anterior pituitary gland.{{cite web|title=gonadotropin|url=http://medical-dictionary.thefreedictionary.com/gonadotropin|work=The Free Dictionary|publisher=Mosby's Medical Dictionary, 8th edition. Elsevier.|access-date=4 June 2012|year=2009}} This secretion is regulated by gonadotropin-releasing hormone (GnRH) produced in the hypothalamus.{{cite web|title=Hormones of the Hypothalamus: Gonadotropin-releasing hormone (GnRH)|url=http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/H/Hypothalamus.html#GnRH|work=Kimball's Biology Pages|publisher=John W. Kimball (The Saylor Foundation)|access-date=4 June 2012|first=John W. |last=Kimball|date=12 February 2011|url-status=dead|archive-url=https://web.archive.org/web/20120627085615/http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/H/Hypothalamus.html#GnRH|archive-date=27 June 2012}}{{cite book | last = Marieb | first = Elaine | title = Anatomy & physiology | publisher = Benjamin-Cummings | page= 915 | year = 2013 | isbn = 978-0-321-88760-3 |oclc=43903780}}

{{Main article|Development of the gonads}}

The gonads develop from three sources; the mesothelium, underlying mesenchyme and the primordial germ cells. Gonads start developing as a common primordium (an organ in the earliest stage of development), in the form of genital ridges,{{cite book |last1=Schoenwolf |first1=Gary C. |title=Larsen's human embryology |date=2015 |publisher=Elsevier |isbn=978-1-4557-0684-6 |oclc=862800082 |page=16 |edition=5th}} at the sixth week, which are only later differentiated to male or female sex organs (except when they are not differentiated). The presence of the SRY gene,{{cite web|title=Human Developmental Genetics|url=http://www.pasteur.fr/ip/easysite/pasteur/en/research/scientific-departments/developmental-biology/units-and-groups/human-developmental-genetics|work=Institut Pasteur|access-date=4 June 2012|url-status=dead|archive-url=https://web.archive.org/web/20120505080019/http://www.pasteur.fr/ip/easysite/pasteur/en/research/scientific-departments/developmental-biology/units-and-groups/human-developmental-genetics|archive-date=5 May 2012}} located on the short arm of the Y chromosome and encoding the testis determining factor, usually determines male sexual differentiation. In the absence of the SRY gene from the Y chromosome, usually the female sex (ovaries instead of testes) will develop. The development of the gonads is a part of the development of the urinary and reproductive organs.{{cn|date=April 2025}}

{{Expand section|date=September 2022}}

The gonads are subject to many diseases, such as hypergonadism, hypogonadism, agonadism, tumors, and cancer, among others.{{Citation needed|date=September 2022}}

A delay in having children is common in the developed world and this delay is often associated with ovarian female infertility and subfertility. Ovarian aging is characterized by progressive decline of the quality and number of oocytes.{{cite journal |vauthors=Park SU, Walsh L, Berkowitz KM |title=Mechanisms of ovarian aging |journal=Reproduction |volume=162 |issue=2 |pages=R19–R33 |date=July 2021 |pmid=33999842 |pmc=9354567 |doi=10.1530/REP-21-0022 }} This decline is likely due, in part, to reduced expression of genes that encode proteins necessary for DNA repair and meiosis.{{cite journal |vauthors=Yang Q, Mumusoglu S, Qin Y, Sun Y, Hsueh AJ |title=A kaleidoscopic view of ovarian genes associated with premature ovarian insufficiency and senescence |journal=FASEB J |volume=35 |issue=8 |pages=e21753 |date=August 2021 |pmid=34233068 |doi=10.1096/fj.202100756R |doi-access=free }}{{cite journal |vauthors=Turan V, Oktay K |title=BRCA-related ATM-mediated DNA double-strand break repair and ovarian aging |journal=Hum Reprod Update |volume=26 |issue=1 |pages=43–57 |date=January 2020 |pmid=31822904 |pmc=6935693 |doi=10.1093/humupd/dmz043 }} Such reduced expression can lead to increased DNA damage and errors in meiotic recombination.

The testes of older men often have sperm abnormalities that can ultimately lead to male infertility. These abnormalities include accumulation of DNA damage and decreased DNA repair ability.{{cite journal |vauthors=Dong S, Chen C, Zhang J, Gao Y, Zeng X, Zhang X |title=Testicular aging, male fertility and beyond |journal=Front Endocrinol (Lausanne) |volume=13 |issue= |pages=1012119 |date=2022 |pmid=36313743 |pmc=9606211 |doi=10.3389/fendo.2022.1012119 |doi-access=free}} During spermatogenesis in the testis, spontaneous new mutations arise and tend to accumulate with age.{{cite book |vauthors=Cioppi F, Casamonti E, Krausz C |title=Genetic Damage in Human Spermatozoa |chapter=Age-Dependent De Novo Mutations During Spermatogenesis and Their Consequences |series=Adv Exp Med Biol |volume=1166 |pages=29–46 |date=2019 |pmid=31301044 |doi=10.1007/978-3-030-21664-1_2 |isbn=978-3-030-21663-4 }}

{{Portal|Anatomy}}

• Gonadosomatic Index
• Hypothalamic–pituitary–gonadal axis

{{Reflist}}

{{Endocrine system anatomy}}

{{Authority control}}

Category:Glands

Category:Endocrine system

Category:Human reproductive system

Category:Sex organs