What is a key feature of androgen insensitivity syndrome?

Androgen insensitivity syndrome (AIS) is characterized by a genetic condition where an individual who is genetically male (with a 46XY karyotype) has cells that are unable to respond to androgens, which are male sex hormones.

In individuals with AIS, despite having a male karyotype, they often develop external female genitalia and secondary sexual characteristics due to the lack of androgen response. A key feature of this syndrome is the presence of testicular development while lacking typical male secondary sexual characteristics, such as pubic and axillary hair, because androgens are not acting on the target tissues. This can result in a phenotype that appears female, including the absence of menarche due to the lack of a functional uterus and ovaries.

The presence of testicular tissue and lack of pubic hair despite a 46XY karyotype aligns with the features of androgen insensitivity syndrome. Therefore, the correct answer highlights a crucial aspect of the syndrome, showcasing the discrepancy between the genotypic sex and the phenotypic expression of secondary sexual characteristics.