Mystery of the wheelie suitcase: how gender stereotypes held back the history of invention

Why have some brilliant innovations - from rolling luggage to electric cars - taken so long to come to market? Macho culture has a lot to answer for

In 1972 an American luggage executive unscrewed four castors from a wardrobe and fixed them to a suitcase. Then he put a strap on his contraption and trotted it gleefully around his house.

This was how Bernard Sadow invented the world's first rolling suitcase. It happened roughly 5,000 years after the invention of the wheel and barely one year after Nasa managed to put two men on the surface of the moon using the largest rocket ever built. We had driven an electric rover with wheels on a foreign heavenly body and even invented the hamster wheel. So why did it take us so long to put wheels on suitcases? This has become something of a classic mystery of innovation.