I'm a childless woman by circumstance. I had always planned, expected, hoped and dreamed that I'd marry and have children, but I'm now in my early 40's and both milestones have eluded me. It's not that I'm not maternal. I have always loved children and I'm a very devoted aunt. It's not that I do not want to be married, either. It's just that, like so many of my college-educated female cohorts of Generation X, marriage and children are to come later, if ever. It wasn't because we delayed marriage and motherhood for education or our careers. It's that we never saw getting a college degree or having a career that offered self-sufficiency as choices -- as our brothers didn't. And the overwhelming majority of us have children only once we are married.

We can debate about why college-educated women get married and have children later than other women, but the important thing to understand is that neither our longer singlehood nor our childlessness mean that we don't love and value family and the children in our lives -- our nieces, nephews, our friends' children, godchildren, little cousins, etc. Yet, while there are more childless women than ever before, we're more often deemed to be "selfish career women" who've lost focus than maternal women who just haven't found the right man (or woman) with whom to have children.

Let's be honest, some moms can be elitist. Whether it's based on the way they choose to parent, e.g. stay-at-home versus working moms or attachment parenting versus another method, or simply because they are mothers, their judgments can create diversions between moms and between moms and non-moms. Some of the childless women in the Savvy Auntie community I launched four years ago for aunts by relation and aunts by choice have shared some of the comments they've heard from friends or relatives who are mothers: "You'll never know love until you're a mother," or "You wouldn't know. You're not a parent."

And yet, for many aunts, their love for the children in their lives is unconditional and boundless. There is nothing they would not do for your kids. The fact that these children are not their own is proof of their devotion.

Of course there are women who do not want to have children of their own -- a completely valid decision -- and some who have no patience for kids. And of course, there are some mothers who are not all that maternal, either. Being maternal is not something that comes from the birth or adoption of a child. After all, Florence Nightingale, Mother Teresa and more recently, Oprah Winfrey, are shining examples of childless women who were and are incredibly charitable with their motherliness.

But one need not be Mother Teresa to show incredible generosity to children not-her-own. Perhaps you know a childless woman who is generous with your children. She might be your sister or a close friend who takes your children out on fantastic adventures, like their first music concert or a big sporting event. Maybe she simply loves to bake cookies with them or play ball in the yard. Perhaps she's the one who paid for the coach or tutor you might not have been able to afford with all your other parenting obligations. Perhaps she's become a trusted confidant to them as they grow older. Or when you were a new mother, perhaps she played with your baby as you took a shower or a much-needed nap. Maybe she's been there for your kids when you, for whatever valid reason, were not able to be there.

To be an active childless aunt is a selfless act. No matter what the relationship, blood or friendship, nearby or miles away, everything an aunt does for a child-not-her-own is a gift. Unlike parenting, there is no obligation to "aunt." But this Savvy Auntie, as I call her, is often overlooked and unacknowledged for all that she does. More so, she's made to feel invisible with the constant spotlight on Hollywood moms and "baby bumps" and all the recent media attention on who is mother enough and if and how moms can have it all.

As the founder of Savvy Auntie, the lifestyle brand for the nearly 50 percent of American women who are not (yet) moms, I wanted to help give moms and dads a way to celebrate and honor the women who do so much for their children. This Sunday, July 22, is the fourth annual Auntie's Day®. Like Mother's Day or Father's Day, it is simply a day set aside to show gratitude to a special member of the family -- Auntie.

You can visit AuntiesDay.com for more information and ideas and for digital posters and ecards you and your kids can use to celebrate the aunt in your kids' lives -- and in your life.

Aunthood is a gift. This day is hers.