Dr. Sheffield is a geneticist at the SGC. After Ba'al arrived on Earth seeking SG-1's help to eliminate his many clones, Dr. Sheffield ran tests on the DNA samples taken from Ba'al and the first clone they captured. She generated distinct DNA profiles of both the host and the Goa'uld symbiote and determined a perfect match across all 13 specific DNA markers, indicating that either the clones were genetically indistinguishable from the real Ba'al, or they were holding two Ba'al clones and the real one was still at large.

Portrayed by: Lesley Ewen

Cross Reference: SGC

Episode Reference: Insiders