Three-quarters of the children feel guilty about receiving help from the Bank of mom and dad to help them with their finances, the new figures suggest.
However, what these guilty offspring do not know is that a growing number of parents do not tell their children exactly how much each sibling in the family earns.
In fact, more than 40 percent of parents over 55 decide how much money to distribute to their children based on how well they are individually.
Tension: Getting help from the Bank of Mom and Dad can strain the siblings
One in five parents with multiple children does not tell their children how much they have given each child, suggests an investigation of the company's launching of shares.
With rising rental and property costs, stagnant wages and higher inflation, many younger people are discovering that they need a financial boost from their parents.
Critics would argue, however, that times have always been difficult and not long ago interest rates were in double figures, putting pressure on millions of hard borrowers.
But, in many cases, children feel guilty for obtaining this support and parents can be financially affected, Key's research suggests.
Recent figures from Legal & General have suggested that one in five parents and grandparents now accept a lower standard of living to help their loved ones on the property ladder, and some even postpone retirement to do so.
A quarter of children under 40 say that financial leaflets they have received from their parents have caused friction with their siblings, show Key's findings.
Interestingly, most descendants aged 40 or younger do not feel they have the right to receive brochures from their parents. Sixty-seven percent reported that their parents do not have an obligation to distribute cash.
But, many of the younger generations harbored concerns about the "intergenerational wealth gap."
16% of parents admitted that they can not afford to give money to their adult children, while 22% say they may have to provide financial support to their own elderly parents.
Commenting on the pressure that mom and dad bank brochures can put on families, Will Hale, CEO of Key, said: "It's natural for parents to want to help their children and grandchildren, but it's very sad if that it comes with emotion. " costs in addition to financial costs.
"In an ideal world, the whole family should participate in discussions about how much money is being paid and, in general, research shows that most would be perfectly happy that siblings receive more if they need more help."
"But, of course, we do not live in an ideal world and, in extreme cases, the bank revolts of mom and dad can end up in court.
"We believe that counseling is key and families should, whenever possible, seek independent help from either financial advisers or lawyers."
The figures released last month suggest that the Mom and Dad Bank may have a deficit of £ 18,000 for the financial support of their adult children.
Tips for lending or giving money to adult children
1. Establish from the beginning if the money is a gift or a loan. If it's a gift, then there should be fewer problems
But if it is a loan, then it is worth seeking legal advice and, especially, if the loan is to buy a property and if your child is married or living with a partner.
2. If you own a home and become the joint owner of your child's property, your interest in the property will be considered a "second home," meaning you will be charged a higher rate of Property Tax. Fiscal on the transaction.
3. If the money is a gift, you could incur an inheritance tax charge and financial advice specialized in estate planning could be valuable.
4. It is important to consider updating your will especially if you have more than one child and potential beneficiaries.