Dr. Barbara Thornfield, M.D., Ph.D. is Lacey Thornfield's mother. Lacey and her mother do not get along very well. Very recently Dr. Thornfield was at a hospital in the Ukraine heading up the Pediatric Cardiology department; she also disarmed land mines in Bosnia the year prior.

In college, Dr. Thornfield belonged to Omega Theta Nu sorority; she subsequently taught Lacey Omega Theta Nu's cheer and secret handshake. She apparently has a fascination with former Secretary of State Henry Kissinger, instructing her assistant Francis to monitor her telephone calls and interrupt her if Kissinger attempts to contact her.