This study will identify how personal beliefs, values and family experiences affect a person's decision as to whether or not to be tested for changes in a gene called BRCA1 or BRCA2. Changes in these genes are associated with a significantly increased risk of breast and ovarian cancer in women, a slightly higher risk of prostate cancer in men, and a slightly higher risk of colon cancer in both men and women.

Families enrolled in the National Cancer Institute's familial cancer research project who also participated in a telephone survey (protocol 78-C-0039) regarding their level of interest in BRCA1/2 testing results may be eligible for this study.

All participants will complete a 20- to 30-minute questionnaire assessing knowledge, risk perception and personality traits, and will participate in an education session to review the following:

• Information about their individual cancer risk, based on family history
• Potential benefits and risks (medical, psychological and social) of BRCA1/2 testing, both for those who test positive and those who test negative
• Overview of DNA testing (what is done and how accurate it may or may not be)
• Medical management options for those at increased risk for breast and ovarian cancer
• Environmental cancer risk factors
• Instruction in breast self-examination

Participants will then be asked whether or not they want to undergo BRCA1/2 testing

Those who want to be tested will be divided into two groups to compare counseling methods (client-centered vs. counselor-driven counseling). A small blood sample (2 to 3 tablespoons) will be drawn for genetic analysis. Test results will be provided in person at a second visit-this may take 6 months or more. A follow-up telephone call 2 weeks after receipt of the test results will address participants' questions and provide support. During a third visit, scheduled 6 months after receipt of the test results, participants will complete questionnaires evaluating mood, attitude, self-esteem, family interactions, cancer screening practices, and other factors. Finally, 1 year after receipt of the test results, participants will be contacted by telephone and asked about their feelings about the test and its outcome.

Individuals who choose not to have gene testing will not participate in any in-person sessions after the initial visit. They will be followed with no more than two telephone interviews to assess their feelings and attitudes related to their decision not to be tested.

Individuals may reconsider and change their mind at any time regarding their decision-whether to be tested or not.

The results of the study will help experts devise the most effective methods of educating and counseling people at high risk for having an altered BRCA1/2 gene.