On Friday, Sharon Greenham, 51, and Darren Greenham, 44, pleaded not guilty at Preston Crown Court to the manslaughter of George Hinds.
Emergency services were called to the scene of the blast in Heysham, Lancashire, in the early hours of May 16 last year.
They found two houses in Mallowdale Avenue had collapsed, with a third seriously damaged.
The Greenhams also pleaded not guilty to damaging a gas meter between January and May 2021 and theft of gas between March and May 2021.
Both will go on trial on October 4, with the hearing estimated to last up to four weeks. A pre-trial review will take place on August 12.
Members of George's family watched proceedings from the front row of the public gallery.
In a tribute issued after the youngster's death, his parents Vicky and Stephen said: "We are devastated at the loss of our beautiful George. He was so precious to us.
"We have no words to describe how we feel and just want time to ourselves to come to terms with what has happened.
"Our beautiful little angel grew his wings today."