Mary was the daughter of Frank Farquarson and his wife, Jessie Carmichael. she had one younger sister called Tudelle Farquarson.

On 21st October 1912, Mary gave birth the child she was carrying while on Titanic. she named her, Mary Margaret Elizabeth Marvin.
She was born in NYC, NY.

After her second marriage to Horace De Camp, Mary gave birth to another child, Julia Janet De Camp. born on 6th February 1915.