Student loans are no doubt one of the biggest challenges that many millennials face as they start looking and establishing their careers. But, millennials are the only ones who are carrying the burden of their student loan debts; even parents are having difficulty, and their retirement getting delayed because of their kids' college loans.

It is natural for families to look for ways to finance their children's higher education, especially today when college costs constantly increases and federal loans have limits. Millions of Americans had Parent Plus loans last year just to support their child's education costs.

One parent, Harlan Crider of Elverson, PA, shared with MarketWatch how he already wants to retire considering that he is already 79. However, he needs to pay $400 a month on loans for his son's college education. He already stretched the repayment term to 30 years so that it becomes more manageable, but with his age, he says that he probably will have to pay for the loan until he is dead.

While it is natural for parents to help their children with debt and education, financial advisers warned that it is not a good trend and the students should be the one who should be taking most of the burden because they are the ones who will reap the benefits of this investment. Now, what is happening is that parents are the ones who carry their children's debts even when they reach or pass retirement age.

According to BIC, parents aged 60 and above should take the time to review their retirement income sources and control their monthly expenses. Although they can consider working longer, it would be better if they shift to investing so that they have resources that they can tap into come their retirement age.