An accidental discovery, the tablet that gave impotent men the chance once more to have natural erections became the fastest selling pill in history and has earned its manufacturer, Pfizer, over $6bn.
The search is now on for a similar drug that could help women. Research is revealing that female sexuality is more complex than expected.
For women suffering from a loss of desire many scientists believe that drugs acting on the brain may be the way forward.
A pioneering Scottish study may have identified just such a drug and begun testing it scientifically.