THEY are the generation that thought their children would grow up and fly the nest.
Now they're doing up the spare room, extending the house and inviting their offspring into their retirement homes, as the trend towards multigenerational living takes hold in many parts of the world.
Growing numbers of young families are forgoing the dream of climbing the property ladder and are returning to their parents to pool costs and responsibilities.
The housing shortage, the rising cost of childcare and an aging population are all contributing to the figures, which are at their highest in four decades in the UK.
More than 500,000 households now contain three generations.
That figure is expected to reach 556,000 by 2019, according to the Intergenerational Foundation think-tank.
There has been a 30% increase in the number of multigenerational households in the past decade, according to figures from the Office for National Statistics.
Clare Gallagher, 25, a publicist, is one such statistic. She swapped her rented flat for the home of her fiance's grandparents in north London.
"The main reason was financial," she said. "We are lucky that they have a big house ... and the mortgage is already paid. It means we get to save money, our three-year-old son gets to spend much more time with his great-grandparents, while we help them with their bills."
In embracing a return to an extended family culture, Britain is moving closer to southern European countries, where the recession has driven it further and faster.
Unlike Britain, where a social stigma is still pinned to those moving back in with their parents, in Spain and Italy, no such shame exists.
The phenomenon is such that major brands are specifically targeting the extended family unit.
Ikea, the Swedish furniture giant, recently ran television commercials in Spain with the slogan: "If two (generations) fit in, three will, too."
One ad featured a middle-aged man who tells his father he has been laid off and asks if he can move home with his wife and children.
Instead of a hostile response, the three generations celebrate together as they plan how to renovate the house.
Daniel Plant, strategy director for Ikea at the media agency Vizeum, said the trend was happening in Britain through the force of financial circumstances.
He believes the fact that a lack of affordable housing, the rising cost of childcare and other factors are affecting everyone means that moving in with parents or in-laws is losing its stigma.
The move comes as a welcome solution to Britain's acute housing shortage and has benefited the beleaguered construction industry.
Loft and basement conversions and home extensions are among the few areas that have witnessed a growth in spending.
Carpenter Oak, based in Devon, is one of the construction firms that has seen orders for house extensions rise by nearly 10% between 2007 and 2010.
"We have noticed a growing number of families combining funds to purchase a site and then co-habiting," managing director Jamie Wilson said. "This trend is likely to continue as house and land prices rise."
Marc Vlessing, co-founder of the affordable-housing scheme Pocket, said: "The phenomenon of 'doubling up' is a welcome solution for a Government grappling with the problem of under-occupied housing. It won't be long before you see politicians trying to give people fiscal reasons for relinquishing their family home."
But shadow housing minister Jack Dromey disagrees: "This is just another example of how, under current housing policy, families are being forced to abandon the dream of ever buying a home of their own."