Donovan's first patent, granted June 12, 1951, covered her waterproof, breathable 'Boater' diaper cover with snap fasteners — a landmark in infant care design.
On June 12, 1951, Marion Donovan was granted U.S. Patent 2,556,800, filed January 19, 1949, for her waterproof diaper cover known as the Boater. Frustrated by leaking cloth diapers and rubber pants that caused diaper rash by trapping moisture against a baby's skin, Donovan set out in her Westport, Connecticut, kitchen to engineer something better.
Her first prototypes were cut from a shower curtain using her own sewing machine; she later refined the design using nylon parachute cloth for durability and breathability, and replaced troublesome safety pins with plastic snap fasteners so parents could no longer accidentally prick their babies. The result was a diaper cover that kept moisture contained without the rubber pants' clamminess, a genuine engineering innovation grounded in everyday maternal frustration.
This patent represents a genuine first: it was the foundational innovation that made the disposable, leakproof diaper cover commercially viable and set the stage for the modern disposable diaper industry. Major manufacturers initially rejected the product, skeptical that a design from a housewife-inventor had commercial merit, so Donovan manufactured and marketed it herself. It debuted at Saks Fifth Avenue in 1949 and became an immediate commercial success, proving there was a lucrative consumer market for better infant care products and paving the way for later disposable diaper technology.