According to Anne K. Mellor, Mary Shelley did live the rather irreligious life that one would suppose she lived given the lack of religion in the novel.

Mary Shelly's mother gave birth to her after only having been in wedlock for five months. The only reason Wollstonecraft and William Godwin decided to marry, since as revolutionaries they were so opposed to the institution of marriage, was to give Mary social respectability understanding the famous name she would be carrying on (Mellor, 2).

William Godwin by James Northcote, 1802.

Her father was an "irreligious philosopher for whom Harriet Lee, a woman he had courted, was too proper" (Mellor, 5). He confessed to Mrs. Clairmont Godwin, his second wife, that there was nothing that had "so much reverence and religion in it as affection to parents.Mary had, as she put it, "an excessive and romantic attachment" to her father. Thus Mrs. Clairmont limited Mary's access to her father. In fact Mary described that her father "was my god . . .& and I remember many childish instances of the excess of attachment I bore for him" (Mellor, 8).

In her relations later in life, Mary Shelley certainly did not morally adhere to the ideas of the time. What was an intense sexual and emotional relationship between Mary and Percy Shelley occurred while he was still married to Harriet Shelley. Also, a part of their attraction to each other was because Shelley knew Mary would have a commitment to revolutionary principles like her parents were and Mary saw in Shelley her father's revolutionary philosophical personality.

Mary's sexual involvement with Percy while he was still a married man also serves as an example of Mary Shelley fostering her mother's ideals of sexual freedom demonstrated by Wollstonecraft's life and her writing.