Along with "how do bees fly?" and "why is Jeremy Kyle still on telly?", "what came first, the chicken or the egg?" is one of the major mysteries in the world today. Or, at least, it was.
Boffins at Sheffield University believe that they've found the answer. Kind-of.
During research into the formation of egg shells, they, while working with colleagues at Warwick University, discovered that a particular chicken protein came first as it only exists within hens' ovaries.
The protein ovocledidin-17 (OC-17) clamps onto tiny particles of calcium carbonate, converting it into calcite crystals thereby creating the hard shell of an egg. And it is the discovery that the OC-17 protein controls the process from the outset that suggests the theory that the chicken came first.
Dr Colin Freeman, from Sheffield University's Department of Engineering Materials, said: "It had long been suspected that the egg came first but now we have the scientific proof that shows that in fact the chicken came first.
"The protein had been identified before and it was linked to egg formation but by examining it closely we have been able to see how it controls the process.
"It's very interesting to find that different types of avian species seem to have a variation of the protein that does the same job".
It is hoped that the discovery can lead to creation of man-made materials.
Now all we need is an answer to the question "how many black turtle necks does Steve Jobs own?"