Parents are providing help with things like housing and groceries, and sometimes directly investing for their children, to give them a head start in a challenging economy

Help with everyday expenses such as groceries and gas can give young adults the financial breathing room to start investing sooner, according to a new report.

Read more about how young adults are coping with today's economy in MarketWatch's coverage of the New American Playbook.

An affordability crisis is straining American families, but that's not stopping many members of Gen Z from investing in the stock market at younger ages - often with some form of support from their parents, who are making sacrifices to help them get ahead.

In many cases, this doesn't mean a direct investment into a child's account.

"For many younger investors, help with everyday expenses creates financial breathing room that can make regular market contributions possible," according to a new survey of investors ages 18 to 34 and parents of young adults conducted by MarketWise, an investment research company.

Among surveyed parents, 57% said they were helping their adult children pay for groceries, while 56% paid their phone bill, 45% provided funds for housing or let their children live at home for free, and 22% were making car payments for their adult children.

These expenses can add up to hundreds or even thousands of dollars each month. The findings come as young people may see stock-market returns as providing a surer path to wealth than paychecks from a 9-to-5 job.

As young Americans struggle with housing affordability - with the typical rent at $1,948 in August, according to Zillow - 25% of young investors who are living rent-free with their parents said they would own no investments at all without their help, and half said their monthly investing would stop if they didn't receive support.

"Depending on where you live," even an income of $100,000 "can be just barely enough or nowhere near it," Audrey Emerson, the owner of Cents of Joy Financial Planning in Bellingham, Wash., recently told MarketWatch. This is especially true for young adults with children.

Related: More 20-somethings are moving in with their parents. Here's how they can build savings - without bankrupting mom and dad

"Family help often acts more like a runway than an engine. It makes it easier to get off the ground, but the young investor is still making decisions and putting in their own money over time," Steven Longenecker, senior editor at MarketWise, told MarketWatch regarding his company's survey.

At a time when Americans' grasp of personal-finance concepts is on the decline and many students don't receive training in financial literacy in school, providing support "doesn't require writing a check," he added. "A parent who helps a child understand a 401(k), opens the conversation about investing, or encourages them to put away even $20 or $50 regularly can give them a starting point into investing that won't jeopardize the parent's own finances."

Meanwhile, 35% of the surveyed young investors - defined as those holding at least one investment account, including any retirement accounts - said they received money from their family that they invested, while16% received a deposit directly into a brokerage account and 13% received a deposit into a retirement account.

Two-thirds of parents told MarketWise that providing this support was hurting them financially, including by reducing the amount they are able to save for themselves (43%), reducing or delaying travel (24%), and adding to debt (24%).

"It's not surprising that young adults are leaning on both family and nontraditional sources for support, but these dynamics are also putting pressure on parents," Emily Irwin, head of private wealth planning at Wells Fargo, said in a statement earlier this year.

In Wells Fargo's survey, two-thirds of parents of adult Gen Z-ers - the generation born between 1997 and 2012 - said they provide financial support to their children. "Open communication, clear expectations, and shared planning can help families navigate this stage together," Irwin said.

More on this: The kids are out of the house, and I saved for college. How are they still spending so much of my money?

"If a parent has the means to help, I think being explicit about the purpose of the money can be valuable, like explaining that you're helping them now because starting early gives their money more time to compound," Longenecker said.

Young investors' most common holdings were mutual funds and exchange-traded funds (71%), followed by individual tech stocks (32%) and other individual stocks (38%), while 30% owned cryptocurrencies, according to MarketWise.