The key to the age-old question apparently lies in the fact that since genetic material does not change throughout an animal's life, the first bird that evolved into a chicken must have initially existed as an embryo inside an egg.
Professor John Brookfield, from England's University of Nottingham, concluded that because of this, the living organism inside the eggshell would have had the same DNA as the chicken it turned into.
The specialist in evolutionary genetics was quoted in a number of newspapers as saying: "Therefore the first living thing which we could say unequivocally was a member of the species would be this first egg. The egg came first."