A friend of mine and I sat down at a bar and come up with a conceptual million seller: the Kevlar Kondom(TM). What neither of us were was organic scientists, nor industrial engineers, so our idea, from my end, was a good one that never went anywhere. However, he went on to other pursuits, and for all I know, he may be, even now, producing the next great advance in both venereal disease and pregnancy protection.
On the other hand, unless the brain decides to wrap the rascal, nothing made by scientists can help. Sort of like the old "if you don't bother to put the seat belts on, they can't save your life."