The karyotype in testicular feminising syndrome is ?

**Core Concept**
Testicular feminizing syndrome, also known as androgen insensitivity syndrome (AIS), is a condition where an individual with a 46,XY karyotype is resistant to androgens (male hormones). This results in the development of female external genitalia despite the presence of testes.

**Why the Correct Answer is Right**
In AIS, the androgen receptor gene is mutated, leading to a non-functional androgen receptor protein. As a result, the individual is unable to respond to androgens, such as testosterone, which are produced by the testes. The lack of androgen effect allows for the development of female external genitalia, whereas the presence of testes indicates a 46,XY karyotype. This condition is often associated with a mutation in the AR gene on the X chromosome.

**Why Each Wrong Option is Incorrect**
* **Option A:** This is not a correct karyotype for testicular feminizing syndrome.
* **Option B:** This is incorrect as it does not accurately represent the karyotype associated with testicular feminizing syndrome.
* **Option D:** This is not the correct karyotype for testicular feminizing syndrome.

**Clinical Pearl / High-Yield Fact**
In individuals with AIS, the presence of blind-ending vagina and testes can be a clue to the diagnosis, and genetic testing for the AR gene mutation can confirm the condition.

**Correct Answer:** C. 46,XY.