Who is Dr. Shapiro from Good in Bed and what is their importance?

Cannie's father, Dr. Shapiro, has been an enigma in her life. He abandoned his family when Cannie was eighteen, and although, he showed up at her graduation from college, he did not attend the graduation itself. Over the course of the novel, Cannie learns that her father is living and working in Los Angeles. He has no wish to be a part of his daughter's life.