There's no way to calculate the value of a mother's kiss, a lullaby or her timeless advice, yet when it comes to grocery shopping, cleaning bathrooms or driving kids to soccer practice, financial reimbursement is a bit easier to compute. Mothers aren't paid for this tireless work, yet they contribute more to the family than many give themselves credit for, say several insurance companies.

One has calculated the annual value of a mother's work at $61,436, which doesn't factor in any income she may earn outside the home.

That "salary" includes helping with homework as a teacher or instructor (based on an hourly rate of $17.85), nursing wounds like a licensed practical nurse ($17.90 an hour), handling family finances as an accountant ($23.83 an hour), and even finding out what the kids are up to as a private detective ($19.78 an hour).

Another website lets mothers add in their own information to get a numerical figure for their financial contribution as a homemaker.

Yet despite knowing these actual dollar figures, no mother receives a check or even public praise for her work, leaving many to refer to motherhood as the unsung, unheralded, "invisible" profession.

In a column on, Mindy Greenstein writes about how the hardest job she's ever tackled has been raising her two sons.

She cites author and former New York Times reporter Ann Crittenden who wrote, "The Price of Motherhood," about how motherhood has been demeaned by both men and women and labeled a step backward for women.

"And yet, as Crittenden points out, that outside world would crumble if mothers weren't propping it up, training and developing the human capital that creates, discovers and maintains the resources on which we depend as a society," Greenstein writes. "The profession of motherhood is the glue that holds together all the goods and services that are documented in the Gross National Product."

As well as nurturers, trainers and developers of human capital, Greenstein also sees mothers as behavioral scientists whose dissertations are their children, though such work is never finished and requires years of patience before results can be seen.

But that title worries Katie Allison Granju, who wrote on that while many tasks in a mother's day constitute jobs in the traditional sense, others, like the role of behavioral scientist, seem far beyond her capabilities.

"After I read this part of Dr. Greenstein's blog post, I thought to myself, 'Wow, that's not a job for which I am qualified in any way, and there's no way anyone would ever actually HIRE me for that position,'" Granju wrote.

Granju continued by saying that perhaps women are wrong to compare their relationships with their children to moneymaking positions, given that such positions often come with specific performance measures and benchmarks.

If motherhood were reduced to meeting specific goals and tasks, "I think many of us — maybe most of us — would be considered abject professional failures," she wrote. "I know that I would. My own failure at this job — if that's how we are characterizing our roles as mothers — would be considered obvious, extreme, and very public."

Yet motherhood is not about being perfect or "employee of the month." It's about seeing beyond the crumb-crusted furniture or a teenager's fluorescent pink hair to the joy in a toddler's potential and the creative capacity of a 15-year-old.

"(Our most important job is) instilling in our kids the confidence that comes from knowing that they're someone special in the world, and the humility that comes from knowing that so is everyone else," Greenstein wrote. "If we do only that, we will have made an enormous contribution to the world, no matter what our other work-related contributions are, and no matter what it says on our tax returns."