The major objective of this article is to present preliminary evidence linking differentiation of self to decisions concerning predictive cancer genetic testing. We also measured the level of stress and distress experienced by individuals in the family when they receive genetic counseling and/or testing for hereditary forms of cancer. This pilot study included 25 pairs of individuals (probands and study partners who were a spouse, sibling, or parent) who called for an appointment at the Ohio State University Cancer Genetics Program. Three hypotheses were generated based on Bowen's Family Systems Theory, and two were supported by the data presented. This pilot study demonstrated that differentiation was associated with the stress associated with the counseling and/or testing situation, and psychological distress for both probands and study partners.