It doesn’t matter how you’re built or what your gender is — one size never fits all, but most consumer products are made with the assumption that one size will fit most.

Maybe you don’t fit comfortably in an airplane seat. Or your bulky smartwatch slips and slides up and down your wrist. Or you go to the restroom and have to put your purse on the icky floor because there’s no shelf in the stall. Maybe you’ve poked yourself with scissors trying to extract a new purchase from its form-fitting plastic packaging, or, even worse, cut yourself on said packaging.

If you’ve suffered because a product didn’t accommodate your size, strength, or needs, then you’ve been a victim of design bias.

Kathryn H. Anthony, a professor at the University of Illinois at Urbana-Champaign, has been teaching graduate architecture students about design bias for more than two decades. Her newest book, “Defined By Design: The Surprising Power of Hidden Gender, Age, and Body Bias in Everyday Products and Places,’’ details the many ways consumer products inconvenience or even hurt us. We spoke with her via phone.

This transcript has been edited and condensed.

Ideas: How did your inquiry begin? Was there an “aha!’’ moment?

Anthony: I’ve been teaching and writing about this topic for over 30 years, mostly on gender issues. Several years ago, I asked my graduate students, many of whom come from other countries, to ask someone who was different from them — either in gender, age, or body size — how they were advantaged or disadvantaged by design. The project grew, and the answers I got were really interesting.

Ideas: What were some things you learned?

Anthony: Shoes are a big problem. Some of the students interviewed Asian women who tend to have smaller feet. When they tried shopping here in the United States, they had a hard time finding their size, so they resorted to online shopping. Of course, you can’t try on shoes that way. You can order them, find out they don’t fit, and send them back. But you’ve wasted a lot of time just because the stores aren’t stocking your size.

We found design bias is in the workplace, too. Some of my students talked to female bartenders who were on the short side, for example, who had to reach up really high to get drinks, glasses, and other things they needed to do their jobs. Their environment simply didn’t work for them.

Ideas: What was the students’ reaction?

Anthony: It was eye-opening. We all have a tendency to look at and experience the world through our own body. It’s not easy to recognize bias against others. But so many of us put up with bad decisions made by designers every single day. It’s exhausting!

Ideas: When you started exploring this topic, did the world begin to feel like a more hostile place?

Anthony: I saw advantages and disadvantages everywhere. I always say an airplane is the best place to be a 5-foot-2 female like me. If you happen to have an empty seat next to you, you can even lie down, which most people can’t do.

But just yesterday I was at the gym trying to do the lat pulldown. I had to jump up and grab the bar — it’s too high for me to reach. And then a guy came up to me and told me I was doing the exercise wrong. He said my hands need to be farther apart. But I actually can’t hold it properly because the grips are too big. Somebody designed that equipment, and they didn’t think about the fact that women come in different shapes and sizes.

In that case, I’m not getting my money’s worth out of my membership, because the designers weren’t thinking about people my size.

Ideas: Where in the design process does the bias begin?

Anthony: There are many excellent designs and designers out there. The most glaring problem is that all too often, even good designers fail to think about the diverse kinds of people who might use their products. It’s too easy to design for people who look just like you.

When I feel disenfranchised by design, I wish that designers could spend a minute feeling the same way.

Ideas: What’s the worst designed group of products?

Anthony: For each person, that answer varies, of course. The worst designed product is the one that’s not working for you. In general, though, I’d say the worst products are those that injure or kill. You’ve heard of wrap rage? When trying to open a package, some people end up in the emergency room with cuts, they may have even cut off a finger. And I’m not just talking about clamshell packaging, but childproof jars, too. By making the world childproof, we’ve made the world dangerous for adults.

I’d also include children’s toys and play equipment that caused injury or death and led to widespread product recalls. The products may be out of production, but the families who discovered the design flaws are still paying the price.

Ideas: I thought you were going to say shoes are the worst.

Anthony: I did read that on 9/11, there were piles of high-heeled shoes found at the stairways of some of the buildings at the World Trade Center. People were evacuating, and they had to take off their shoes because they couldn’t run fast enough. If you have high-heeled shoes in an emergency, it could be a life or death matter. I can wear them from a parking lot to a building, but that’s about it.

Ideas: You organized the products in your book by type — clothing, furniture, toys, and so on. If you’d split things instead by gender, age, or body bias, where would most of the products wind up?

Anthony: Biases are often intertwined, so I can’t answer that. When the design of products and spaces doesn’t take into account the needs of people such as menstruating or breastfeeding women, the elderly, young children, taller men, that is bias plain and simple. That’s the problem with the ready-made world.

Ideas: How did you avoid bias in the design of your book?

Anthony: We wanted to be aesthetically pleasing and present information in a universal way. It’s available digitally, so people can control their own text sizes. In the conceptual design of the book, I tried my best to address the whole spectrum of humanity — tall, short, thin, heavy, young, old.

Ideas: Did you ever discuss the font?

Anthony: No, and that’s a good point. It never came up.

Rachel Slade, an Ideas contributor, is a Boston-area writer and editor.