Do you wonder if your kids will have your back when you’re older? Apparently the answer is a surprising yes.

That’s the good news in a conversation many people are having these days — around aging parents — that comes courtesy of the third biennial “Fidelity Investments Family & Finance Study.” Less heartening is that nearly 4 in 10 families seem to be suffering from what can only be described as — hats off to “Cool Hand Luke” for this — a failure to communicate.

Let’s start by paying homage to at least certain offspring and giving them their due credit:

• While 93 percent of parents felt it would “unacceptable” to become financially dependent on their kids, 70 percent of the adult children had no qualms about opening their wallets.

• Children were much more likely to expect that they, or a sibling, would care for an ill parent than their moms and dads were (47 percent vs. 11 percent).

“Despite this welcome news for parents, the study suggests several areas where they [parents] need to speak up to ensure their wishes are heard, as it appears the children may not be getting the message,” says John Sweeney, Fidelity’s executive vice president of retirement and investing strategies.

Whether it is estate execution, long-term caregiving during an illness, or help in managing investments and retirement finances, it often turns out that the very child that parents expect will handle things doesn’t have a clue the responsibility will fall to him or her. (Reaching as high as 44 percent of children, in the case of helping to manage their parents’ household expenses.)

Part of this miscommunication is attributed to “timing,” given that only 33 percent of parents and their offspring agree on when it’s “appropriate” to initiate conversation related to aging. Before retirement? Upon entering retirement? Closer to when health and/or finances become an issue? (The correct answer? Before retirement.)

Compounding the problem is that even when those conversations do occur, the study found, they’re not as detailed as they should be.

Think about it: Has your family discussed, say, how it will cover the estimated $245,0000 the average couple can expect to spend on healthcare throughout their golden years?

Probably not. But as, Sweeney notes, “At some point, every family will face issues relating to aging — perhaps even dementia — and there are real emotional and financial consequences when family conversations either don’t happen or lack sufficient depth.”

If peace of mind is important to you — and at least 93 percent of both parents and children reported attaining it after having had those all-important talks — online tools can help get you there.

Fidelity, for example, has a variety of resources available at fidelity.com/families

that, among other things, list the documents you’ll need should a key financial decision-maker die.

After all, “Cool Hand Luke” moments are best saved for the movies.