when marcella reached puberty but did not begin to menstruate, her parents took her in for medical testing. tests revealed that marcella's chromosomes are xy and her gonads are producing testosterone, but she developed feminine external genitalia because her body is unable to respond to testosterone. marcella is diagnosed with . .

marcella is diagnosed with androgen insensitivity syndrome (AIS).

It is also called feminizing testis syndrome (FTS) or male pseudo-hermaphroditism, is a disorder of sexual differentiation related to an absence or abnormality of the function of androgenic tissue receptors. So the patient cannot develop male organs even if he has the Y chromosome and a normal level of androgen.

Marcella is diagnosed with complete androgen insensitivity syndrome.
Complete androgen insensitivity syndrome is an intersex condition which occurs due to complete inability of the body to respond to androgenic hormones such as testosterone. This condition occurs to genetically male individuals (who has one X and one Y chromosome). Affected individuals have the external sex characteristics of females, but do not have a uterus and therefore are unable to menstruate.