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The Forgotten Black Woman Inventor Who Revolutionized Menstrual Pads

Mary Beatrice Davidson Kenner was a self-taught inventor who created the sanitary belt and filed five patents in her lifetime.
Illustration by Shreyas Ravikrishnan.

When I was growing up, all the scientific heroes and geniuses I learned about were men. Or more specifically, white men. As the story of Mary Beatrice Davidson Kenner proves, that's just plain historical inaccuracy. There have been thousands of women inventors, scientists and technologists—they just never got the recognition they deserved.

While writing the Forgotten Women book series, I wanted to pay tribute to these unsung heroes. Each book contains 48 illustrated profiles of women from history (the number 48 was chosen to reflect the total number of women who have been awarded the Nobel Prize in its 116-year history).


Women were barred from the corridors of most scientific establishments and academic institutions for centuries, but they carried on regardless. They transformed their bedrooms into laboratories, turned coat hangers into scientific equipment, and in the case of Kenner, saved and scrimped for their own patents.

Forgotten Women: The Scientists is a love letter to their ingenuity and endurance. As the following excerpt shows, nobody exemplifies that better than Kenner—a self-taught inventor who filed more patents than any other African-American woman in history.

Mary Beatrice Davidson Kenner (1912–2006) always had trouble sleeping when she was growing up in Charlotte, North Carolina. Her mother would leave for work in the morning through the squeaky door at the back of their house and the noise would wake Kenner up. “So I said one day, ‘Mom, don’t you think someone could invent a self-oiling door hinge?’" She was only six at the time, but she set about the task with all the seriousness of a born inventor. “I [hurt] my hands trying to make something that, in my mind, would be good for the door,” she said. “After that I dropped it, but never forgot it.”

You could say that skill and ingenuity was in Kenner’s blood. Her maternal grandfather had invented a tricolor light signal to guide trains, and her sister, Mildred Davidson Austin Smith, grew up to patent her own family board game and sell it commercially. Her preacher father, Sidney Nathaniel Davidson, even made a go of transforming the family hobby into a full-time career. Around 1914, Sidney patented a clothes presser that would fit in a suitcase and press trousers while a traveller was en route to his destination, but he turned down a New York company’s $20,000 offer in favour of attempting to manufacture and sell it himself. The result was a failure: he produced only a single presser, which he sold for the paltry sum of $14.


Her father’s experience didn’t put Kenner off inventing, and her idea for the door hinge ignited a spark deep inside her. New ideas for inventions would wake her up from sleep. She occupied herself drawing up models and building them. While other children her age were drawing fanciful aeroplanes and sports cars, Kenner was making thoughtful plans for a convertible roof that would go over the folding rumble seat of a car, where back-seat passengers were usually exposed to the elements. When she saw water dripping off a closed umbrella and onto the door, she came up with a sponge tip that would go on the end and soak up the rainwater. She even drew up plans for a portable ashtray that would attach itself to a cigarette packet.

This pragmatic, do-it-yourself approach defined her inventions for the rest of her life. But while her creations were often geared toward sensible solutions for everyday problems, Kenner could tell from an early age that she had a skill that not many possessed. When her family moved to Washington DC in 1924, Kenner would stalk the halls of the United States Patent and Trademark Office, trying to work out if someone had beaten her to it and led a patent for an invention first. The 12-year-old didn’t find any that had done so.

Photo via Getty Images.

In 1931 Kenner graduated from high school and earned a place at the prestigious Howard University, but was forced to drop out a year and a half into her course due to financial pressures. She took on odd jobs such as babysitting before landing a position as a federal employee, but she continued tinkering in her spare time. The perennial problem was money; filing a patent was, and is, an expensive business. Today, a basic utility patent can cost several hundred dollars.


By 1957 Kenner had saved enough money to her first ever patent: a belt for sanitary napkins. It was long before the advent of disposable pads, and women were still using cloth pads and rags during their period. Kenner proposed an adjustable belt with an inbuilt, moisture-proof napkin pocket, making it less likely that menstrual blood could leak and stain clothes.

“One day I was contacted by a company that expressed an interest in marketing my idea. I was so jubilant,” she said. “I saw houses, cars, and everything about to come my way.” A company rep drove to Kenner’s house in Washington to meet with their prospective client. “Sorry to say, when they found out I was black, their interest dropped. The representative went back to New York and informed me the company was no longer interested.”

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Undeterred, Kenner continued inventing for all her adult life. She eventually filed five patents in total, more than any other African-American woman in history. Again, she continued to draw inspiration from her daily life. When her sister Mildred developed multiple sclerosis and had to get around with a walking frame, Kenner patented a serving tray and a soft pocket that could be attached to the frame, allowing Mildred to carry things around with her. She also patented a toilet tissue holder that made sure that the loose end of a roll was always within reach, and a back washer that could be attached to the wall of a shower to help people clean hard-to-reach parts of their back.

Kenner did not receive any college degree or professional training, and she never became rich from her inventions. But that was incidental; like her father and grandfather before her, she did it out of love for the craft. Most of all, she believed that anyone could become an inventor as long as they put their mind to it: “Every person is born with a creative mind,” she said. “Everyone has that ability.”