Intersex topics
Human rights and legal issues Compulsory sterilization Discrimination Human rights reports Legal recognition Malta declaration Medical interventions Sex assignment Sex characteristics (legal term) Yogyakarta Principles
Medicine and biology Disorders of sex development Genetic diagnosis Definitions Medical interventions history Orchidometer Phall-O-Meter Prader scale Quigley scale Sexual differentiation more...
Society and culture Endosex (antonym) Civil society organizations Fictional characters‎ Films Flag Intersex and LGBT Literature People Religion Military US Researchers Sex verification in sports Television
History and events History of surgery timeline Intersex Awareness Day Intersex Day of Remembrance International Intersex Forum
Rights by country Argentina Australia Canada Chile China Colombia France Germany Kenya Malta Mexico Nepal New Zealand South Africa Spain Switzerland Taiwan Uganda United Kingdom United States
See also Hermaphrodite Children's rights Genital modification and mutilation Disability rights Gender LGBT Androgyny Anti-gender movement Non-binary Non-binary recognition Queer theory Third gender Transgender Medical ethics Rights Sex Sex differences
v t e

The Prader scale or Prader staging, named after Andrea Prader, is a coarse rating system for the measurement of the degree of virilization of the genitalia of the human body^[1][2] and is similar to the Quigley scale. It primarily relates to virilization of the female genitalia in cases of congenital adrenal hyperplasia (CAH) and identifies five distinct stages, but in recent times has been used to describe the range of differentiation of genitalia, with normal infant presentation being shown on either end of the scale, female on the left (0) and male on the right (6).^[3]

Staging

• An infant rated at Stage 0 would be considered as having a normal vulva.^[4]
• In Stage 1, the vulva has a mildly large clitoris (clitoromegaly) and slightly reduced vaginal opening size. This degree may go unnoticed or may be simply assumed to be within normal variation.^[4]
• For Stage 2, genitalia are obviously abnormal to the eye, with a phallus intermediate in size and a small vaginal opening with separate urethral opening.^[4] Posterior labial fusion will be present.
• Stage 3 shows a further enlarged phallus, with a single urogenital sinus^[4] and almost complete fusion of the labia.
• Stage 4 looks more male than female, with an empty scrotum and a phallus the size of a normal penis, but not quite free enough of the perineum to be pulled onto the abdomen toward the umbilicus (i.e., what is termed a chordee in a male). The single small urethral/vaginal opening at the base or on the shaft of the phallus would be considered a hypospadias in a male. X-rays taken after dye injection into this opening reveal the internal connection with the upper vagina and uterus. This common opening can predispose to urinary obstruction and infection.^{[citation needed]}
• Stage 5 denotes complete male virilization, with a normally formed penis with the urethral opening at or near the tip. The scrotum is normally formed but empty. The internal pelvic organs include normal ovaries and uterus, and the vagina connects internally with the urethra as in Stage 4. These infants are not visibly ambiguous are usually assumed to be ordinary boys with undescended testicles. In most cases, the diagnosis of CAH is not suspected until signs of salt-wasting develop a week later.
• Stage 6 indicates a normal penis and scrotum, with no hypospadias present and normal testicles.^[5][6][7]

Controversy

While the scale has been defined as a grading system for "abnormal" genitalia,^[2] the concept that atypical genitals are necessarily abnormal is contested. An opinion paper by the Swiss National Advisory Centre for Biomedical Ethics advises that "not infrequently" variations from sex norms may not be pathological or require medical treatment.^[8] Similarly, an Australian Senate Committee report on involuntary sterilization determined that research "regarding 'adequate' or 'normal' genitals, particularly for women, raises some disturbing questions", including preferences influenced by doctors' specialism and gender.^[9]

Related concepts

Numerous clinical scales and measurement systems exist to define genitals as normal male or female, or "abnormal", including the orchidometer, Quigley scale and the satirical Phall-O-Meter.^{[citation needed]}