Even if we grant your unwarranted assertion that "the genesis of life on Earth must be from an extra terrestrial source", that source would itself have had to evolve elsewhere in the Universe. If that source was itself seeded from another extraterrestrial source (inasmuch as the word has any meaning beyond Earth), that source also had to evolve somewhere else. And we only have around 14 thousand million years to play with.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'
