Bombay, now Mumbai, on 28 December 1937,[9] and is the son of Naval Tata (born in Surat). His biological maternal grandmother had been the sister of Hirabai Tata, wife of group founder Jamshedji Tata. His biological father, Hormusji Tata, had belonged to the broader Tata family; Naval therefore was a Tata by birth. Parents Naval and Sonoo separated in 1948 when Ratan was 10, and he was subsequently raised by the widow of Sir Ratanji Tata,