Kids living with their parents into their late-20s are making it harder for young families to buy the traditional family home.

Baby Boomers and early Gen-Xers are holding onto their large homes twice as long as 10 years ago, according to Domain, to make room for their adult children.

The subsequent scarcity is driving up prices for the market and leaving a gap in downsizers.

KPMG demographer Bernard Salt said the trend towards living with parents was part of a delayed adulthood.

He says many young Australians weren’t graduating to genuine adulthood until 29.

Salt told Ross and John the increased importance placed on education and training was the key factor.

“Over the last generation, and particularly over the past decade, the nurturing phase of the life cycle has extended,” he said.

“These days … there is greater training phase in the life cycle; you need secondary school, university education or some sort of further training.

“Then there’s getting into the work force … building up a deposit for a house and moving out.

“So what was possible a generation ago — moving out of the home at 21, 22 or 23 — I think has kicked out five or six years or so.”

Click PLAY to hear Ross and John chat further with Bernard Salt