Medical science established

The human body and the medical field was an area of science that was not so clearly established/formed. Scientists focused on inventions to make everyday life easier, but sickness and injury was treated with traditional ways.

"Despite the exciting advances that took place in science and medicine in the seventeenth and eighteenth centuries, it was only in the nineteenth century that medicine itself became scientific. This was largely the result of the integration of the natural sciences into medical theory. During the eighteenth century the foundations of scientific medicine were first established."

(http://www.bookrags.com/research/overview-medicine-1800-1899-scit-051234/)

Since the human body was an unknown field, Mary Shelley made a good choice by experimenting with it. She gives Dr.Frankenstein such an ambition and passion towards a field of science that is waiting for a revolutionary movement to happen. It just so happens that he was the initiator of the major movement in the medical/human body field.
-Michael