The point at which children leave home is a momentous one for their entire household.

It marks the transition to adulthood and, for their parents, the moment when they may be left with the proverbial ’empty nest’.

Yet sociologists have mapped out how the departure is often not a definitive break.

They discovered in the late 1980s that many children leave only to return later, in part as a result of the financial pressures of trying to forge their own path in life.

So common was the pattern, in fact, that a phrase – ‘boomerang children’ – was coined.

Fast-forward several decades and we find that the sort of economic issues which once obliged young adults to live with their parents once again are now so acutely felt that some never really leave at all.

That much has been set out in data from the Office for National Statistics (ONS).

It showed that young adults are now more likely to live with their parents than individuals of a similar age group a decade ago. In all, just under 29 per cent of those aged between 20 and 34 reside in the family home.

In my opinion, the finding surely merits consideration of the reasons why. As a family lawyer, however, I am not just interested in the cause but the effect: what consequences the situation may have.

After all, our twenties are commonly the age when we really strive to make our way in the world of grown-ups, establishing a career, relationship and – possibly – a family of our own.

One of the main reasons cited by commentators for why individuals of this age move back in with their parents is quite simply the cost involved in taking a first step on the property ladder.

A different set of figures published by the ONS demonstrated that the average house in the UK now costs £291,000.

Furthermore, the average monthly rent paid by tenants across the country has also continued to climb.

Perhaps unsurprisingly – and also maybe coincidentally, given the latest statistics – the average age at which people buy their first homes in England and Wales has risen to 34.

It means that, for many young people, a critical portion of their lives will have passed before they can escape the sort of financial gravity which ties them to their parents and prevents them achieving true independence.

There are, of course, some parents who may relish the opportunity to look after a child longer than previous generations might have expected.

Even so, there are practical and financial issues to contend with which can create problems on both sides, no matter the amount of goodwill from parents or children.

They can be compounded when a child eager to maintain a degree of their own life moves into the family home with a partner.

In such a situation, there is even more of a premium on privacy and space, something which would not have been a consideration for parents in an ’empty nest’.

Such difficulties are not absolutely new. Nine years ago, my colleague Sam Hall wrote on this ‘blog how some step-parents saw their own relationships pushed to breaking point by returning children.

I would suggest that the potential tensions caused by continuing to accommodate children who never actually left home in the first place can be just as severe, if the Hall Brown case load is anything to go by.

For some parents, an answer lies in paying to help their children out of the family home and into one of their own.

However, that is not without its own complications.

Mothers and fathers who have children wanting to move in with their own partners will naturally want to make sure that they are protected should those relationships fail.

That is not necessarily being pessimistic. Whilst we don’t know how many cohabitees break-up and when, we do know – again, courtesy of the ONS – that one-sixth of marriages end within 10 years of spouses exchanging vows.

It is wise, therefore, to ensure that any support from the so-called ‘Bank of Mum and Dad’ is regulated or ringfenced.

If a child is to marry, protection is best done via a pre-nuptial agreement, setting out who brought what to the relationship and what might happen in the event of a divorce.

Should children cohabit with their boyfriends or girlfriends, it is wise to put a cohabitation agreement in place but – even more particularly – with a document known as a declaration of trust.

What that does is specify who contributes what to the purchase of a property, meaning that sums contributed by parents towards a house deposit may not have to be divided if a child and their partner end up going their separate ways.

Whilst there are people who regard such discussions as wholly unromantic, the frequency of break-ups and divorce makes it very sensible.

In addition, there are few signs on the horizon that the economic picture is set to improve and, as a result, we might reasonably expect more young adults to be living with their parents for just a little while longer.