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It has been suggested that this article or section be merged with [[::Guevedoche|Guevedoche]]. (Discuss)
5-alpha-reductase deficiency
ICD-10 E291, Q563
ICD-9 257.2, 752.7
OMIM 264600
DiseasesDB 11
MedlinePlus [1]
eMedicine ped/1980
MeSH [2]

5-alpha-reductase deficiency (5-ARD) is an Intersex condition caused by a mutation of the 5-alpha reductase type 2 gene.[1] It is also known as Guevedoche in some cultures.


5-alpha-reductase is an enzyme that converts testosterone to dihydrotestosterone (DHT) in peripheral tissues. DHT is a potent androgen, necessary for the development of male external genitalia in utero.

DHT deficiency results in ambiguous external genitalia at birth. The condition affects only chromosomal males (i.e., those with XY chromosomes). Individuals are born with Male Gonads, but appear to have Female Primary sex characteristics. However, due to the normal action of Müllerian inhibiting factor produced by the testis in utero, individuals with 5-ARD lack a uterus and Fallopian tubes and possess testicles and Wolffian structures.

Problems produced by 5-ARD

DHT is the primary hormone in-utero that masculinises the appearance of the external genitalia. In individuals with 5-ARD, these can vary from normal male external genitalia, to ambiguous genitalia, to normal female genitalia.

In individuals with feminised or ambiguous genitalia, there is a tendency towards an enlarged clitoris, or microphallus, and the urethra may attach to the phallus. This structure may be capable of ejaculation. Where the external genitalia appear female, the "pseudovagina" consists only of the lower third of a normal vagina. In the later cases the Wolffian ducts may terminate in the perineum or in the pseudovagina. 5-ARD constitutes a variety of intersexual conditions.

Individuals with 5-ARD are normally raised as girls. However, come puberty, a variety of sequelae occur. Notably, individuals have Primary Amenorrhoea, and may experience virilisation. This may include descending of the testes, hirsuitism and deepening of the voice. Extending into adulthood, individuals do not experience male-pattern baldness [3]. As 5-DHT is a far more potent androgen than testosterone alone, all virilisation may be reduced compared to males without 5-ARD, or may be absent.

In individuals with undescended testis, there is a high rate of testicular cancer. This has been used as an argument for orchidectomy in the past.

Gender and 5-ARD

Individuals with 5-ARD are often raised as girls, and develop a female gender identity. Some, however, may develop a male gender identity, and can present with apparent gender identity disorder.

As 5-ARD is an intersex condition, some individuals may have had genital surgery or orchidectomy as children in order to feminise them. This can complicate gender transition if the individual forms a male gender identity, but has been raised as female.


Individuals with 5-ARD are generally capable of producing viable sperm, however artificial insemination techniques or in-vitro fertilisation are necessary.

Individuals with 5-ARD are not able to become pregnant or produce ova.

5-ARD in the Dominican Republic and Papua New Guinea

See also: third sex

Clusters of cases have been studied in the Dominican Republic and Papua New Guinea, and local names for the condition include 'Guevedoche' or 'Guevedoces' ('testes at twelve', 'penis at twelve'), 'Machihembras' ('first women, then man'), and 'Kwolu-aatmwol' ('female thing transforming into male thing').

Cultural significance

  • Jeffrey Eugenides won a Pulitzer Prize for his 2003 novel Middlesex, which explores this deficiency.
  • Quentin Costa, a character on the television show Nip/Tuck, has this condition.
  • Documentaries on the condition include "Guevote: The Way I Feel Is How I Am" ("Guevote: So wie ich mich fuehle, bin ich"), 1996, by filmmaker Rolando Sánchez,[2] and "The Fight to be Male", 1979, British Broadcasting Company.

See also


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