Khanna was adopted and raised by foster parents who were relatives of his biological parents. Khanna lived in Thakurdwar near Girgaon and attended St. Sebastians Goan High School in Girgaon, along with his friend Ravi Kapoor, who later took the stage name Jeetendra, and whose mothers were friends.[13] Khanna gradually started taking interest in theatre and did a lot of stage and theater plays in his school[14] and college days and won many prizes in the inter college drama competitions.[15] Khanna became a rare newcomer who struggled in his own MG sports car to get work in theatre and films in the early sixties.[16] Both friends later studied in Kishinchand Chellaram College(KC).[17] When Jeetendra went for his first film audition, it was Khanna who tutored. Khanna's uncle changed Khanna's first name to Rajesh when Khanna decided to join films. His friends and his wife called him Kaka (Uncle).[18]
Adult life

Khanna was adopted and raised by foster parents who were relatives of his biological parents. Khanna lived in Thakurdwar near Girgaon and attended St. Sebastians Goan High School in Girgaon, along with his friend Ravi Kapoor, who later took the stage name Jeetendra, and whose mothers were friends Khanna gradually started taking interest in theatre and did a lot of stage and theater plays in his school and college days and won many prizes in the inter college drama competitions. Khanna became a rare newcomer who struggled in his own MG sports car to get work in theatre and films in the early sixties. Both friends later studied in Kishinchand Chellaram College(KC). When Jeetendra went for his first film audition, it was Khanna who tutored. Khanna's uncle changed Khanna's first name to Rajesh when Khanna decided to join films. His friends and his wife called him Kaka (Uncle).

Source: http://www.bollywoodmantra.com/news/iconic-hero-rajesh-khanna-turns-69/8377/

He doesnt have parents and siblings