Frankenstein touches so many different topics. It is a really dense and well written story.
The author talks about creation and how crossing boundaries by abusing of science. It talks about how people will react once man is able to create life and how legitimate and/or real that life would be in the eyes of humanity.
It talks about natural laws and the absolute power of nature. The raw power (as in lightnings) and even the power to heal one's mind (because the Dr. goes to the mountains to rest).
There's also a lot of deception and isolation in the story. Frankenstein behaves in a completely different way with his family and you also feel him quite isolated from the world.