The gonad is the organ that makes gamete
A gamete is a cell that fuses with another cell during fertilization in organisms that reproduce sexually...

s. The gonads in males are the testes and the gonads in females are the ovaries. The product, gametes, are haploid germ cells. For example, spermatozoon
A spermatozoon is a motile sperm cell, or moving form of the haploid cell that is the male gamete. A spermatozoon joins an ovum to form a zygote...

 and egg
An ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...

 cells are gametes. Although scientifically, the term "gonad" can refer to either male gonads (testes) or female gonads (ovaries
The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...

), the vernacular
A vernacular is the native language or native dialect of a specific population, as opposed to a language of wider communication that is not native to the population, such as a national language or lingua franca.- Etymology :The term is not a recent one...

, or slang
Slang is the use of informal words and expressions that are not considered standard in the speaker's language or dialect but are considered more acceptable when used socially. Slang is often to be found in areas of the lexicon that refer to things considered taboo...

, use of "gonads" (or "nads") usually only refers to the testes.


The gonads are controlled hormonally by luteinizing hormone
Luteinizing hormone
Luteinizing hormone is a hormone produced by the anterior pituitary gland. In females, an acute rise of LH called the LH surge triggers ovulation and development of the corpus luteum. In males, where LH had also been called interstitial cell-stimulating hormone , it stimulates Leydig cell...

 (LH) and follicle-stimulating hormone
Follicle-stimulating hormone
Follicle-stimulating hormone is a hormone found in humans and other animals. It is synthesized and secreted by gonadotrophs of the anterior pituitary gland. FSH regulates the development, growth, pubertal maturation, and reproductive processes of the body. FSH and Luteinizing hormone act...

 (FSH) secreted by the anterior pituitary gland. This secretion is, in turn, controlled by the hypothalamus
The Hypothalamus is a portion of the brain that contains a number of small nuclei with a variety of functions...

' gonadotropin-releasing hormone
Gonadotropin-releasing hormone
Gonadotropin-releasing hormone , also known as Luteinizing-hormone-releasing hormone and luliberin, is a tropic peptide hormone responsible for the release of follicle-stimulating hormone and luteinizing hormone from the anterior pituitary. GnRH is synthesized and released from neurons within...



Gonads start developing as a common anlage, in the form of gonadal ridge
Gonadal ridge
In embryology, the gonadal ridge is the precursor to the gonads. The gonadal ridge initially consists mainly of mesenchyme and cells of underlying mesonephric origin. Once oogonia enter this area they attempt to associate with these somatic cells...

s, and only later are differentiated to male or female sex organ
Sex organ
A sex organ, or primary sexual characteristic, as narrowly defined, is any of the anatomical parts of the body which are involved in sexual reproduction and constitute the reproductive system in a complex organism; flowers are the reproductive organs of flowering plants, cones are the reproductive...

s. The presence of the SRY
SRY is a sex-determining gene on the Y chromosome in the therians .This intronless gene encodes a transcription factor that is a member of the SOX gene family of DNA-binding proteins...

A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

, located on the Y chromosome
Y chromosome
The Y chromosome is one of the two sex-determining chromosomes in most mammals, including humans. In mammals, it contains the gene SRY, which triggers testis development if present. The human Y chromosome is composed of about 60 million base pairs...

 and encoding the testis determining factor
Testis determining factor
Testis-determining factor is a general term for the gene that results in maleness in humans and some other species.Certain genes cause chemical reactions that result in the development of testes...

, determines male sexual differentiation. In the absence of the SRY gene from the Y chromosome, the female sex (ovaries instead of testis) will develop.

The development of gonads is a part of the development of the urinary and reproductive organs
Development of the urinary and reproductive organs
The development of the urinary and reproductive organs as a part of the prenatal development, concerns the urinary system and sex organs. The latter is a part of the stages of sexual differentiation....


See also

  • Gonadosomatic index
    Gonadosomatic Index
    The gonadosomatic index, abbreviated as GSI, is the calculation of the gonad mass as a proportion of the total body mass. It is represented by the formula: GSI = [Gonad Weight / Total Tissue Weight] x 100 . It is a tool for measuring the sexual maturity of animals in correlation to ovary...

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