Becoming and being a mother is – to put it mildly – a heavy number.

The shift from child-free personhood to motherhood is viscerally transformative. Every push during labour edges a woman closer to changes that are lifelong and irreversible. A child is not just for Christmas. These days, most children are more and more likely to hang around for quite a while, long past 18 for sure, and often return to the family home well into adulthood.

This week, researchers at the London School of Economics (LSE) published a study on the effects on parents of adult children returning to live in the family home after time living away. The notion of ‘boomerang kids’ is the new normal for a third of young adults. The impossibility of home ownership, the woeful wasting away of an adequate supply of social housing and the immorally high cost of private renting, the gig economy and the introduction of university tuition fees and student loans (as opposed to grants) have all played their part in re-filling what was once an empty nest. The outlook is bleak, with numbers of returners set to rise over the coming years.

Currently, 3.4 million young adults in the UK aged between 20-34 years are living chez Mum and Dad, an increase of 5% over a period of 20 years. Males are much more likely to return home than females. Whilst boomeranging clearly has a negative impact on the autonomy and development of young adults who find themselves back in their childhood beds (complete with Pokemon quilt covers and matching wallpaper), the consequences for their parents can be devastating. The LSE research - carried out across 17 European countries on 99,000 parents aged between 50-75 years - shows that having an adult child move back home impacts significantly and adversely on parents’ health and wellbeing. The study states that the overall consequences for parents are comparable to having a chronic illness or disability. Researchers measured the impact across four areas: control, autonomy, pleasure and self-realisation. All areas were adversely affected by adult children returning home and a significant number of participants viewed their return as a “violation of this life-course stage”. Clearly, it’s not much fun for the parents, even if it is an economic necessity for the returning young adult. And there are no quick fixes for a whole generation who can’t afford to live independently.

The liberation from nearly two decades of parenting when a child first leaves home, can be challenging. I remember wandering around my house like a hungry ghost, looking for ‘disappeared’ kids (and their retinues) to plate up meals to. For a long time, I continued to shop for the masses until my freezer was full to bursting with batches of uneaten and unwanted chilli con carne, macaroni cheese and lentil soup. I eventually cottoned on and began to see distinct advantages in cooking for one or, even better, not cooking at all but instead grazing at the kitchen counter listening to crime podcasts whilst staring aimlessly out of the window onto the park below. A new kind of bliss after years of the hegemony of mealtimes. My budget also perked up as I no longer had to run my home as a kind of serviced facility, requiring daily restocking of basics such as toilet rolls, bread, toothpaste, soap powder, cereal. All of this left more time and space to think about the world beyond domesticity and child-rearing.

For most fifty-something parents, the empty-nest stage is both ending and beginning. It heralds the start of something different, even if it does feel trepidatious. Finding time for others who are not biologically tethered to us can open up new avenues of meaning and experience. Challenging ourselves to re-examine the way we live, the routines we’ve developed and the kind of relationships we have, are all necessary for personal growth, creativity and general health. It’s almost impossible to conduct this kind of life inventory with adult children living under the same roof because our default position is always to care for them and put their needs first – even if they’re nearly hitting 30 and perfectly able to fend for themselves. It’s high time governments realised that unless we have affordable housing for young adults, the growing number of cuckoos in the nest will soon spill over into all kinds of social and emotional messiness, marked by a real decline in the mental and physical health of late middle aged parents.