Carrie Cariello, a mother of five from New Hampshire, writes a blog about her family’s experiences with autism. Her son, Jack, 10, was diagnosed when he was 18 months old.

But Carrie’s post on Jan. 19, titled “I Know What Causes Autism,” offered a particularly poignant look at all of the scientific guesswork. It has received more than 1.6 million views.

Amid a measles outbreak fueled by unvaccinated children — many never immunized because their parents erroneously believe the measles vaccine causes autism — Carrie spoke to TODAY.com about vaccinations.

“Our experience with autism is unrelated to vaccines,” Carrie said. "I wrote this blog post to demonstrate a mother's divided heart when it comes to autism; how we balance the need to know the cause with our commitment to understanding the child standing right in front of us.”

Carrie Cariello NBC News

I was surfing the Internet and came across a headline proclaiming autism and circumcision are linked. I couldn’t help myself. I laughed out loud.

In no certain order, I have read the following explanations for autism over the years:

Autism is caused by mercury.

Autism is caused by lead.

Autism begins with poor maternal bonding.

Certain pesticides may trigger autism.

Plastics.

Gluten aggravates autism spectrum disorder.

People with autism should eat more strawberries.

Too much automotive exhaust is a leading cause of autism.

Chemicals found on non-stick cookware may trigger autism.

The one about maternal bonding is sort of painful for me. The truth is, I did have a hard time bonding with infant Jack. The little guy shrieked and whined and cried for a solid year. He started sleeping through the night at six weeks, and stopped at three months.

But I am certain there is no one on earth more bonded to this boy now, and guess what? He still has autism.

I am happy to announce that I do know what caused Jack’s autism, and without further ado, I’d like to tell you.

Wait for it.

It’s kind of a big deal.

Drum roll, please.

Jack has autism because, as his 5-year-old brother Henry says, he was bornd-ed with it.

Yes, I believe autism is a genetic condition. I believe that somehow my husband’s DNA mixed up with my DNA and together we had a child who thinks Wednesday is orange. Perhaps his unique genetic coding makes him more sensitive to things in our environment like lead and mercury and plastic.

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I don’t know about the strawberry thing though.

I was in a coffee shop last week and a woman came up and introduced herself to me. She said her daughter, Lily, is in Jack’s fifth grade class. I nodded and smiled, took my cup of coffee and turned to leave.

“Wait,” she touched my arm. “I just wanted to tell you something. Lily told me that a boy called Jack weird the other day in class.”

I cringed. “Oh, well, yes. That happens.”

“Lily said she told the boy that Jack isn’t weird. She told him he’s exactly the way he’s supposed to be.”

You can see my dilemma. If I start running around declaring autism an epidemic and screeching about how we need to find out where it’s coming from and who started it and how to cure it, well, that sort of contradicts the whole message of acceptance and tolerance and open-mindedness.

This fragile glass house we’ve been working so hard to build over the past decade will explode into a thousand tiny pieces.

But on the other hand, it sort of is an epidemic. Other families are going to have babies and maybe they would like to have some idea of how to prevent this tricky spectrum disorder from striking. My own children will have their children, and if autism is indeed caused by automotive exhaust, it would be good to know so we could all buy electric cars.

At the same time, I don’t want to focus so much on the what and when and where and how that I forget about the who.

Because I don’t care where it came from.

But I am kind of curious.

It doesn’t matter to me why Jack has autism.

But it might be good information to have.

There’s nothing wrong with him.

Maybe there’s a little something wrong with him because he just spent the last forty-five minutes talking about all the different kinds of gum that Wal-Mart sells.

I wouldn’t change a thing.

I might change a few things.

I celebrate autism and all of its spectacular wonder.

I hate autism because it makes my son talk about gum and Wal-Mart so much.

He is broken.

He is whole.

Autism is no one’s fault.

Maybe I should stop using Tupperware and make him eat strawberries even though he hates them and re-paint the house to make sure there is no lead on the walls or the windowsills.

Maybe I should have loved him harder, deeper, more when he was a tiny swaddled baby squirming in my arms.

Maybe this is my fault.

As you can see, my feelings about Jack’s autism diagnosis are as complicated as a prism with a thousand colors and angles and light.

I am not a scientist. I am not smart enough for that. But I am a mother. And although I am not really smart enough for that either, I do know autism from that angle.

When you live with someone who has autism, you say the phrase for now a lot.

For now, the radio is on the right station.

For now, he’s not screaming.

For now, he’s sleeping.

For now, he’s safe.

So, for now, I’m going to believe Jack’s autism is because of DNA and RNA and heredity.

For now, I will try to add broad splashes of green and blue and purple and orange to science’s black and white brush strokes. Together, we will fill in autism’s canvas until a clearer picture comes forward.

I don’t know exactly what that picture looks like yet, but I like to imagine it is a utopia of sorts.

There are tall, blonde girls named Lily and boys with glasses named Jack.

And if you look hard enough, you can see a glass house in the distance—almost on the horizon. If you look closer, you will see a sentence etched into the front door. This one sentence—this collection of eight words—well, they are very, very big.

The first time I heard them, I was in a coffee shop.

“He’s exactly the way he’s supposed to be.”