Gad was born on January 28th, 1929. Gad's father was Franz Stiassny and his mother was Kaete Weiss. His paternal grandparents were Siegmund Stiassny and Marie Schostal. He had two brothers and a sister, named Shim'on, Ezra and Rachel. He was the oldest of the four children. He died at the age of 80 in January 2009.