Mary Shelley lived an unusual life for a woman in nineteenth century England. Her parents were both unconventional and famous, and Mary was not bound by as many restrictions as most women of her generation. She still must have felt the pressure to conform to societal stereotypes, but she lived a life that was free by many standards of her age.
What is interesting about Frankenstein is that, though the author is a woman, the female characters in the book are all completely dependent on men and depicted as the selfless "angel in the house" so prevalent in Victorian literature. A woman's place was in the home and in relationship to a man. She had no agency of her own. This is reflected in the characters of Elizabeth, Victor's mother, and Justine, the Frankenstein family's servant. Both Elizabeth and Victor's mother were rescued by Victor's father and lived only to serve the family. Victor even thought of Elizabeth as his possession. Justine lived to serve the family, and when the monster killed Victor's younger brother, Justine went to her death willingly for the murder, even though she was innocent.
The book is narrated by Robert Walton in letters to his sister. Even she is depicted only in relationship to men, as a wife and a sister, with no personality of her own. Shelley's representation of gender in her novel reflected the way women were viewed during her lifetime.