The Prader scale or Prader staging, named after

Andrea Prader Andrea is a given name which is common worldwide for both males and females, cognate to Andreas, Andrej and Andrew. Origin of the name The name derives from the Greek word ἀνήρ (''anēr''), genitive ἀνδρός (''andrós''), that re ...

, is a coarse rating system for the measurement of the degree of

virilization Virilization or masculinization is the biological development of adult male characteristics in young males or females. Most of the changes of virilization are produced by androgens. Virilization is most commonly used in three medical and biology ...

of the

genitalia A sex organ (or reproductive organ) is any part of an animal or plant that is involved in sexual reproduction. The reproductive organs together constitute the reproductive system. In animals, the testis in the male, and the ovary in the female, a ...

of the human body and is similar to the

Quigley scale The Quigley scale is a descriptive, visual system of phenotypic grading that defines seven classes between "fully masculinized" and "fully feminized" genitalia. It was proposed by pediatric endocrinologist Charmian A. Quigley et al. in 1995. It is ...

. It primarily relates to virilization of the female genitalia in cases of

congenital adrenal hyperplasia Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive disorders characterized by impaired cortisol synthesis. It results from the deficiency of one of the five enzymes required for the synthesis of cortisol in the adrenal cort ...

(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).

Staging

* An infant rated at Stage 0 would be considered as having normal female external genitalia. * Stage 1 has a mildly large clitoris and slightly reduced vaginal opening size. This degree may go unnoticed or may be simply assumed to be within normal variation. * 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. Posterior labial fusion will be present. * Stage 3 shows a further enlarged phallus, with a single

urogenital sinus The urogenital sinus is a part of the human body only present in the development of the urinary and reproductive organs. It is the ventral part of the cloaca, formed after the cloaca separates from the anal canal during the fourth to seventh w ...

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 The perineum in humans is the space between the anus and scrotum in the male, or between the anus and the vulva in the female. The perineum is the region of the body between the pubic symphysis (pubic arch) and the coccyx (tail bone), includi ...

to be pulled onto the abdomen toward the umbilicus (i.e., what is termed a

chordee Chordee is a condition in which the head of the penis curves downward or upward, at the junction of the head and shaft of the penis. The curvature is usually most obvious during erection, but resistance to straightening is often apparent in the ...

in a male). The single small urethral/vaginal opening at the base or on the shaft of the phallus would be considered a

hypospadias Hypospadias is a common variation in fetal development of the penis in which the urethra does not open from its usual location in the head of the penis. It is the second-most common birth abnormality of the male reproductive system, affecting abou ...

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 Urinary retention is an inability to completely empty the bladder. Onset can be sudden or gradual. When of sudden onset, symptoms include an inability to urinate and lower abdominal pain. When of gradual onset, symptoms may include urinary incont ...

and

infection An infection is the invasion of tissues by pathogens, their multiplication, and the reaction of host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable dis ...

. * 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 testes. In most cases, the diagnosis of CAH is not suspected until signs of salt-wasting develop a week later. * Stage 6 indicates normal male presentation, with no hypospadias present and normal testes.

Controversy

While the scale has been defined as a grading system for "abnormal" genitalia, 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. 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.

Related concepts

Numerous clinical scales and measurement systems exist to define genitals as normal male or female, or "abnormal", including the

orchidometer An orchidometer (or orchiometer) is a medical instrument used to measure the volume of the testicles. The orchidometer was introduced in 1966 by Swiss pediatric endocrinologist Andrea Prader of the University of Zurich. It consists of a string of ...

and the satirical

Phall-O-Meter The Phall-O-meter is a satirical measure that critiques medical standards for normal male and female phalluses. The tool was developed by Kiira Triea (Denise Tree) based on a concept by Suzanne Kessler and is used to demonstrate concerns with the ...

References

External links

The Prader Scale - About Kids Health
{{Male congenital anomalies of genital organs , state=collapsed Male genital procedures Female genital procedures Intersex and medicine

Staging

Controversy

Related concepts

See also

References

External links