I stood at the highest point of the sloping playground, able to see both kids running, laughing and playing. Hands on hips, sunglasses on head and car keys tucked in my back pocket. I loved every moment.

Ninety-degree scorching days had finally surrendered to a burst of unexpected coolness. The trees felt it, the kids felt it and we were all just a little more energized, even while the hint of cool reminded me another summer was fading.

Joyful screeches filled the air. We had arrived at the playground to find it swarming with older kids, probably eight, nine and 10-year-olds. Charlie and Emma stood cautiously at first, watching the older kids race by, tagging and yelling and storming. Slowly, they began to find their way. I stood back and watched.

While Emma looked on with a somewhat awe-struck shyness, Charlie was clearly just waiting for his moment. The child has never had a second of shyness–everyone is a friend to be greeted heartily, from the grumpy old man ambling through Target to the stoic cashier with a nose ring and a cold, dead stare. He cracks and warms them all.

As he began to feel more at home, he began to race back and forth along a bridge-like iron walkway, arms in the air, right leg swinging out from his hip, rarely bending. He couldn’t keep pace with the kids, but he could race alongside whichever one happened to be beside him for the moment.

“Ewwwww!!!!” screeched a red-haired girl. “Ewwwww!!!” She was maybe 8 or 9, smaller than many of the other kids but louder and shriller. She was pointing to Charlie while half running away and half lingering to stay near him, head over her shoulder and eyeing his every move.

“He’s weird!” she exclaimed, and dashed away.

I couldn’t breathe for a moment. How was this happening so soon to my baby? At three-years-old, he’s had his share of play dates with other children who have special needs and other children who are developing typically. No child had ever pointed at my son and said anything about his differences.

My eyes followed Charlie, knowing he didn’t understand what she had said. I glanced at Emma, knowing one day, when she did understand, she would kick that little girl’s butt. It didn’t help.

“He’s an AIL-ien!” the little girl shrieked as she ran past him again and beckoned to the kids around her, some who ignored her, some who looked at her for a moment, looked at Charlie and kept playing.

“He’s an AIL-ien! He’s an AIL-ien!” she continued to yell.

The metal bridge’s railing separated my hands from her neck. I was so taken aback; I was speechless and incapable of a proper response. I scanned the perimeter, searching for any accountable adult who might have heard her and could respond. Nothing.

Adults I now realize were daycare employees, not parents, stood together on one side of the playground, half watching the kids and half talking amongst themselves. No one else was noticing this little girl. My heart was breaking, and I slid my sunglasses down to cover my swelling eyes as Emma toddled past and grinned at me.

How could I be tearing up on a children’s playground? I thought. This is ridiculous. I turned toward the offender and recited lines in my head like, “That’s not very nice,” and, “Please don’t call children names.”

Then I heard her.

“AIL-iens! AIL-iens!! All the BABIES are AIL-iens!” She was pointing at Emma, now. My chest heaved and I drowned in a moment of relief. She was grouping the little’s together. It had nothing to do with Charlie’s differences, or if it did, she had moved on to a commonality among those who weren’t like her and her friends. To her, Charlie and Emma were different because they were tiny. They were little and, thankfully, blissfully unaware of this child’s categorization.

Annoyed that she was still an unkind child who enjoyed picking on toddlers, I relaxed knowing that she was being unkind to an entire universe of toddlers, not just my helpless son who happens to have an extra chromosome, the inability to communicate with spoken words and a gait that stands out from the gazelles on the playground.

I’ll never forget that moment, and I vowed that my children would be grounded for their rest of their childhoods if I ever heard them speak of another child that way.

But it made me realize how vital it will be to begin talking about kindness long before Charlie and Emma can understand its emotion. Like manners and my relentless prompting, “Say please! Say thank you!” The kids don’t understand what those words mean now, other than that they temporarily appease a demanding mother. But one day, those words will be habit.

Now my job is to make kindness an unbreakable habit.