What is a defining characteristic of Testicular Feminization Syndrome?

Testicular Feminization Syndrome, also known as Androgen Insensitivity Syndrome (AIS), is characterized by the body's inability to respond to androgens (male hormones), despite having a male chromosomal pattern. Individuals with this syndrome typically have a 46, XY chromosomal pattern, which is often associated with male development. However, due to the insensitivity to androgens, they develop external female characteristics.

The defining characteristic in this context relates to hormonal and physiological changes experienced by individuals with this condition. The presence of primary amenorrhea is significant, as these individuals do not have functioning uterine structures to facilitate menstruation due to the lack of responsiveness to androgens. The absence of menstruation is one of the first clinical signs that may lead to further investigation, which can reveal the individual's genetic makeup and the insensitivity to androgens resulting in female external genitalia.

While other options might relate to various aspects of sex differentiation disorders, they do not specifically define Testicular Feminization Syndrome in the same way that primary amenorrhea does. For instance, the option mentioning 46 XX chromosomes incorrectly identifies the chromosomal structure typical in this syndrome; patients actually have XY chromosomes. The presence of normal internal female genitalia does not occur in