It has been speculated before, that Mars could very well be the origin of life on Earth, but lately evidence suggesting this theory are growing.
At the early stages of Earth, Mars was supposedly more suitable candidate for biological life forms to form, as Scientists at the Goldschmidt gathering in Florence were told. As geochemist Professor Steven Benner summarised his theory that the "seeds" of life probably arrived on Earth in meteorites as a consequence of impacts or volcanic eruptions. The material Professor Benner believes to be the crucial catalyst for the life to begin is called molybdenum or rather the oxidised mineral form of the described element. His argument is, this form of molybdenum could not be available on Earth as its early stages. A very interesting theory by the professor is also the one suggesting that Earth at the time was mostly covered in water, which would have prevented forming of RNA, a cousins of DNA, which is believed to be the first genetic molecule. Early Mars on the other hand, had its surface covered with significantly smaller amount of water.