Candace is a normal-looking 15-year-old girl but has never had a menstrual perio

The lack of a uterus suggests two possibilities. Two tests are required to distinguish between these two causes of primary amenorrhea, determining the karyotype (chromosome analysis) and measuring the testosterone levels.

The first possibility in a girl with breasts but without a uterus is that she is genetically female, 46XX, but had abnormal mullerian development of the reproductive organs. If this is the case, testosterone levels will be normal.

The second possibility is that she is genetically male, 46XY, but her androgen receptors are insensitive to the male hormones that would have caused her to develop male genitalia. This condition is called Complete Androgen Insensitivity Syndrome. Because she has the Y chromosome she will have high levels of testosterone when tested, she is simply insensitive to this hormone.

Testosterone is produced by adrenal glands and testes. The presence of elevated testosterone combined with absence of a uterus suggests that she has testes rather than ovaries. The lack of masculinization indicates that her tissues do not respond to the testosterone that is present. There is no uterus because she is genetically male. This can be confirmed by examining her chromosomes.