The 'Rocket Man' hitmaker said he remembers the disadvantages of being an only child, so he and Partner David Furnish are now hoping to increase the size of their family, reported Contactmusic.
"I spent it in my room, listening to music if my parents were arguing," John, 65, says of his own youth.
"I think it's difficult to be an only child, and to be an only child of someone famous," he added.
The musician also acknowledged that a brother or sister may help Zachary get over an uncomfortable situation that may arise from other children, given that his 17-month-old son has two fathers.
"I know when he goes to school there's going to be an awful lot of pressure, and I know he's going to have people saying, 'You don't have a mummy.' It's going to happen. We talked about it before we had him. I want someone to be at his side and back him up. We shall see," said John, who married longtime partner Furnish in 2005.
