Deep down, beneath my surly, jaded sarcasm, I'm a crunchy, loving hippie at heart, so I'm a really big fan of the concept that it takes a village to raise a child. Of course your family (the people who raised you and grew up with you, are an important part of that village) but so are the people you meet and choose to bring into your little tribe. Many of the other moms I meet are similarly thankful for the fact that they are lucky enough to have a BFF that is their kid's best aunt.
Growing up, between my parents' friends and grandparents' friends, I had approximately 794 "aunties" and "uncles," many of whom I am still close to. So it warms my heart — as a mother, friend, and person being hit with a wave of nostalgia — to see my kids bake cookies with "Uncle" Brian, or give a hug to "Auntie" Nikyda. "Auntie" Katy, my BFF since high school, actually moved around the world when I was just a few months pregnant with my first child. In fact, she announced her move on the same night I announced my pregnancy (or, rather, was outed when someone discovered I wasn't toasting). And when I say "around the world," I'm not being my typical, hyperbolic self: she moved from New York City to Sydney-friggin'-Australia sort of on a whim. Still, 10,000 miles has not kept her from being a wonderful auntie to my children. She keeps up with their lives, she sends them delightful, Ozzie themed books, toys, and clothing, and whenever she comes stateside to visit she makes time for them.
My kids have amazing "actual" aunts (and uncles) but I'm so glad my friends have extended their family a little wider, as are the ladies I asked to tell me why their BFF is the best aunt a kid could ask for.