Two teenagers sit on a bed watching TV (Betsie Van der Meer-Stone-Getty Images)
The summer vacation is one of childhood's sacred cows, but it's increasingly coming at a high cost for families. 

Americans will spend $55 billion this summer to enroll their kids in day and sleep-away camps and for other activities, such as sports teams, pool memberships and arts programs, according to an American Express (AXP) report. 

That boils down to $856 per child, a 40% jump from 2012, the study found. 

The summer vacation from school, which typically lasts from mid-June through late August, is often thought to be a relic of America's agrarian past, although one sociology professor argues that the belief is a misconception.

Instead, according to Bob Thaler, an assistant professor of sociology at Saginaw Valley State University, the summer break was created for urban families because cities were "hot, dusty, smelly, uncomfortable places to live in summer."

While many families would love to skip camp payments, they're increasingly necessary, given that about 71% of women with children now work. 

Most American families view the summer break either with joy (from the kids' point of view) or with dread (many parents). But aside from the toll on Americans' pocketbooks, there's another cost to be paid. 

Summer vacation disproportionately hurts low-income students, as Slate's Matthew Yglesias points out. [Slate is owned by Microsoft (MSFT), as is MSN moneyNOW.] The idle time during summer break results in the average student's shedding one month of learning, but low-income students lose even more ground, a 2011 Rand study found.

Adding to the problem is that each summer vacation magnifies the problem for low-income students because the learning loss is cumulative over time, the study found. That may play out in even more difficulties for low-income kids to get ahead or make it to college. 

At a time when social mobility is hotly debated -- mounting evidence shows that it's not always easy for low-income kids to climb the income ladder -- here's one idea: abolish summer vacation. 

Sure, it wouldn't be popular with kids and companies already hawking back-to-school gear, such as Wal-Mart (WMT) and Apple (AAPL). But given the hit not only to Americans' pocketbooks but to schoolkids' achievement levels, it's an idea worth considering.

Follow Aimee Picchi on Twitter at @aimeepicchi.

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