Surprise: a book about creating life has a lot to say (or, at least ask) about life and consciousness. Like, "Are we really just born this way?" And, "How much can we blame our parents for, honestly?" And, "Does playing Mass Effect 29 really make us more violent?" Okay, the last one is a little bit of a stretch—but Frankenstein does wonder how our reading habits form our minds and attitudes. If Mary Shelley had been writing in the 21st century, she probably would have had Frankenstein pick up an Xbox controller. (And hopefully have suggested a little counseling.)
Shelley suggests that all men, women, and monsters are born essentially the same, and we're made different by our experiences.
Frankenstein suggests that our experiences are only part of our personalities; we're all born with essential parts of our consciousness formed.