My sister and I are unalike.

My sister and I are so unalike I required a DNA sample before I agreed to include her in my will.

“Cindy” makes lists.

She makes lists of the lists she is going to make.

I make lists of the lists I am not going to make.

In a recent email, she wrote, “Yes, I do write out a grocery list. Lately, I’ve been going to the store about every two weeks instead of every week. At home I keep a list of things that I might want from many different places. Then before I go to Kroger or Target or wherever, I make a new list for only that particular store.

“Today I had a lengthy list. A few things weren’t available because of the holiday season, but I was only getting those things to try a new recipe. I’ll put those things back on a list for the next time I go.”

I wrote back, “As soon as possible, read your last email out loud to your therapist. And send another DNA sample.”

Me? I go to the grocery store every other day, partly to shop and partly to remind myself why I live alone.

Something happens to people in grocery stores that doesn’t anywhere else.

Anne Teak, a Stanford University psychologist, commented, “Shoppers will stare at cans they’ve seen all their lives and wonder if, after a century, Campbell’s might have added sea bass or rum to its tomato soup. I can’t explain it.”

She can’t explain human behavior and she’s a psychologist.

How can a sister and a brother be so different?

I’m not convinced we’re related.

We look different. She was homecoming queen and I have a face like a first baseman’s mitt, and right now it’s the bottom of the ninth.

Cindy does what she’s told. Her doctor insisted that she schedule appointments to have her ears cleaned with cotton swabs.

And she does.

“Don’t they sell Q-tips in Michigan?” I asked.

HBO has been showing “The Bee Gees: How Can You Mend a Broken Heart,” a documentary that focuses on brothers Barry, Robin, Maurice, and touches on Andy.

Barry is the only living Bee Gee.

Their biggest success came during the era of Top Forty radio when they had four or five songs in constant rotation.

Good for them; hard on the disc jockeys, as one admits.

For a while their music was unavoidable on AM radio.

The brothers squabbled, particularly Barry and Robin, broke up, got back together and had hit records in the 1990s.

There is no doubt they were brothers.

Not a speck of contrary data.

Sure, my sister and I have the same last name. But that says little. “Smith” is the most common surname in the United States.

I want to make it clear that I am not ashamed of her. In fact, I am proud to be her brother, if, in fact, we are related.

But now and then something will come up, like her lists, that makes me question our relationship.

On separate occasions she has used the words “veggie” and “fridge.” Once in the same sentence.

I closed my eyes and let the moment pass.

P. S. Did you know that Shirley MacLaine and Warren Beatty are sister and brother?

Craig Marshall Smith is an artist, educator and Highlands Ranch resident. He can be reached at craigmarshallsmith@comcast.net.