Specialist in the genitourinary system of males and the urinary system of females

Urologist

Explanation:

The person who is involved in the study of the genitourinary system of both males and female is known as the urologist.

The genitourinary system is the system of the organs which are involved in both the sexual and urinary function in the body. The word is formed by the uro from urine and logist - for the person who studies forms the word urologist.

Thus, the urologist is the correct answer.