Though not much of a movie-goer, I faithfully read movie reviews. My hands down favorite reviewer is Anthony Lane of the New Yorker. In the current New York Review of Books Geoffrey O'Brien reviews Ridley Scott's movie "Prometheus." and though I think the review's ending becomes rather feverish, it may provide some insight into fears that need addressing:

What is at issue, it seems, is not the horror of alien life but of life in any form; not the existence of monsters but the monstrousness of existing. The dread that rises to the surface here hints at a culture variously afraid of sex, afraid of Darwin, afraid of DNA, afraid of aliens afraid no matter which way it looks, forward or backward and finding its way at last, as a last resort, to a planet of death.After that the only destination left is the Great Unknown or more precisely (and perhaps we have this to look forward to as a sequel) the home planet of the Manichaean demiurges who engineered us randomly and then just as randomly set out to eradicate us.

The full review is here (but available only to subscribers).