NEW YORK (MainStreet) — Getting your 30-something offspring to leave is not as easy as simply putting his bags on the doorstep. Quite the contrary, it is an involved legal process. A lot more complicated than the romcom movie “Failure to Launch” would have you believe - and it is a problem that is becoming increasingly more common.

More and more today’s 20 and 30-somethings are living with their parents. It is not always a happy arrangement.

According to Pew Research Survey, a full one out of four adults who move back in with - or never left - their parents homes are saying the arrangement has a deleterious effect on their relationship.

Pew states 61% of adults ages 25 to 34 have friends or family members have moved back in with their parents over the past few years because of economic conditions. 29$ of parents of adult children report that a child of theirs came back home to live with them in the past few years for economic reasons.

Multi-generational family households are at the highest rate they have been since the 1950’s said Pew. The figure has increased to 21.6 percent in 2010, the most recent available data, from 15.8 percent in 2000.

The nadir of this cohort was in 1980. Then only 11% of of 25- to 34-year-olds lived in multigenerational households. But the amount has risen steadily since then. It spiked upward beginning with the 2007 recession.

With the 2014 college grads greeting the real world with an average of $33,000 in student debt, and with job prospects grim -- Millennials face a 15.2% unemployment rate compared to the 6.1% in the rest of the population -- often there's no choice but to move back in with Mom and Dad and eat Wheaties in the basement.

If everyone gets along, there is no problem. But more and more parents are losing their patience. When parents have reached their limit and want their offspring out, they find it is one of the most emotionally exhausting familial events there is. It ranks right up there with a divorce in terms of gut wrenching experiences.

Free legal advice blogs and parenting chatrooms are jammed with parents seeking advice. This June 2012 question to Ask-a-Lawyer Free Legal Advice.com is typical:

Can you legally throw out an adult child without a legal eviction?

Question Details: A 22-year-old moved back in with parents almost a year ago and will not follow rules (keep his room clean or work more than two days a week to afford his bill or pay his own way).

So what happens when the arrangement turns sour?

There are different legal avenues which apply to different circumstances that parents can pursue. One is an “action of ejectment.” An eviction would be used if there is a landlord- tenant relationship. But absent this, the ejectment is the procedure.

Ejectments come into play if the slacker is living in a vacation home or a house the parents were using for a rental property or a property they that they are putting up for sale. This involves going to court and getting an order to vacate the property.

The other option is a "defiant trespass." This comes into play if the slacker is living in the parents' house and refuses to leave.

“If the child is an adult, the parents have no legal obligation to house him,” said Pat Biswanger of the law firm of Palmarella and Curry, in suburban Philadelphia. “In the case of an adult child who refuses to leave, the parents can call the police and ask them to prosecute the child for defiant trespass. If the police won’t do it for some reason, the parents can go to the magisterial district justice and file a private complaint for defiant trespass and get a court order telling the child to leave.”

One thing legal experts do caution against is what is known as “self-help” measures. The law provides that even though the person is a guest in your house or is staying in your guest house or vacation home etc., the person cannot be summarily removed.

What are self-help measures? The law defines self-help as “the protection of one’s own person or property through personal means without resort to the legal process.” They include things like turning off the water or changing the locks. If you do, the person may have a cause of action against you.

What if threats of violence are made?

“I know of cases where the adult child is mentally ill and abuses, or threatens to abuse, his parents,” Biswanger responded. “In that case, the parents can go to court and get a protection from abuse order that would forbid the child from entering the premises. The parents should contact a domestic violence program for assistance in those circumstances. They can be very helpful.”

What about if the scions vandalize the vacation home or a house the parents are putting up for sale?

Biswanger said that if the adult offspring became vindictive and vandalized the place, the parents would have to file criminal mischief or similar charges, and then seek recovery from him and/or their insurance company.

So next time your kid - or anyone - who is down on his luck and needs a place to stay “temporarily” - keep in mind if he refuses to leave, you have to take legal action. Just throwing the person out or calling the police is not going to get it done.

The old saw about “no good deed goes unpunished” is a fact of life when one has a kid who is failing to launch.

--Written by Michael P. Tremoglie for MainStreet