I can see that this would be a central theme in the story. In Frankenstein, by Mary Shelley, Victor Frankenstein discovers a way to reanimate dead flesh. Though his reasons for doing so were admirable (to save those who might die), in essence, he plays "God" by giving life, where only God should do so—certainly not man. This would reflect the moral environment in which Shelley lived.
This particular theme that you have chosen has amazing similarities to the debate that rages around today, for example, about cloning. The ethical questions of creating life fuel a heated debate between the religious and scientific communities. It is not the only morally-based debate in contemporary society (stem cell research is another). Surprisingly though, this story was written in the 1800s, but the theme of man playing God is perhaps even more relevant now.
Frankenstein was based on a nightmare Mary had and discussions with friends. It was also considered a fantastical warning in response to the Industrial Revolution in England; ironically, an idea that was considered totally bizarre and impossible at the time, presents a viable accomplishment today.
If I were to write an essay about God vs. science, I think I would connect the basic premise in the novel to the real potential within the scientific community today of "creating life."
Central to the thinking of the Romanticists is that reason is not the only path to truth--intuition is an important path--and that science can only instruct on how to do things. So, for your research, you may wish to investigate the precepts of Romanticism and how it comes into sharp contrast with science and biological studies of Erasmus Darwin, grandfather to Charles, the search of alchemists for the legendary philosopher's stone, as well as the technological advancements of the Industrial Revolution that greatly affected the Romantic writers.
Another aspect you may wish to research is Frankenstein's connection to Milton's Paradise Lost, a book that the creature himself reads. The creature identifies himself with Adam, and later he identifies with Satan:
I am thy creature; I ought to be thy Adam,but I am rather the fallen angel, whom thou drivest from joy for no misdeed. Everywhere I see bliss, from I alone am irrevocably excluded. I was benevolent and good; misery made me a fiend. Make me happy again, and I shall be good.
Here the Romantic notion of friendship enters. As a godly quality, the friendship of men was highly revered during Shelley's time; it was perceived as an elevated love. By pursuing only science, Victor Frankenstein follows a path that elimnates his humanity, and he is thus destroyed, just as the creature is destroyed by his lack of friendship and human love.
Then, of course, do not forget the subtitle, The Modern Promethesus, and its implications. According to critic Joyce Carol Oates, in her essay, "Frankenstein's Fallen Angel," which is cited below Frankenstein is a demonic parody of Milton's God (or extension); Ms. Oates writes,
he "is" Promethesus plasticator, the creator of mankind; but at the same time, by his own account, he is totally unable to control the behavior of his own demon.
Another essay that you may wish to read on enotes, is George V. Griffith's "Frankenstein in the Context of the Romantic Era" which is also cited for you below.