Here's a conundrum that got me very puzzled after I was introduced to it by Elizabeth Renter of NerdWallet: Why are single parents so much richer than single non-parents?

Why it matters: It's generally understood that the more money you make, the more money you'll have. But that doesn't seem to be the case when you look at the Fed's triennial survey of consumer finances.

Where it stands: Since the 2013 survey, single parents have been getting much richer — in 2022, the median such adult was worth $50,750, almost three times the $18,023 of nine years previously. (All numbers are in inflation-adjusted 2022 dollars.)

• Single non-parents under the age of 55, meanwhile, both earned more than the single parents for the entire period and didn't have any kids to support. And yet their net worth lagged, hovering around the $20,000 level the whole time.

Be smart: Here's our best guess for how to resolve this puzzle.

• The way most Americans build wealth isn't by making more money, it's by owning a home.

Between 2007 and 2022, single non-parents fell out of love with homeownership. While the single-parent homeownership rate stayed relatively steady over that time — around 50% — the rate for single non-parents fell to a mere 29%.

Between the lines: It's hard to be footloose and fancy-free once you're raising a child; instead, you tend to seek stability and certainty. That means you're much more likely to want to buy a home. There are also societal expectations that parents should be homeowners.

By the numbers: In a survey Harris Poll conducted for NerdWallet, 47% of renters who are parents with children under age 18 say they are embarrassed to say they rent rather than own.

• That compares with just 29% of non-parent renters.

In other words: There's strong and measurable societal pressure to buy a home once you have a child — and that pressure, in turn, can end up translating into wealth.

The bottom line: That higher net worth for single parents probably isn't very liquid.