Here is the design of a clinical trial:

Official Title: A Randomized Controlled Trial Comparing Self-referred Message to Family-referred Message Promoting Men's Adherence to Evidence-based Guidelines on BRCA1/2 Germline Genetic Testing: a Study Protocol

Included conditions:
- BRCA1 Mutation
- BRCA2 Mutation
- Psychosocial Factors

Study Armgroups:
- {'label': 'First-person gain-framed self-referred messages', 'type': 'ACTIVE_COMPARATOR', 'description': 'This group receives a message in which the main character is a man who speaks in first-person. The character is a man with a sister with a BRCA germline mutation. After this common introduction, the content of the messages becomes different.\n\nGroup 1 receives a self-referred narrative message in which the protagonist explains that he has decided to have a genetic test to discover BRCA germline mutation. He then explains the reasons why this decision is important to himself (e.g., implementing preventive behaviors) and what are the possible benefits for the individual.', 'interventionNames': ['Behavioral: Message comparison']}
- {'label': 'First-person gain-framed family-referred messages', 'type': 'EXPERIMENTAL', 'description': 'This group receives a message in which the main character is a man who speaks in first-person. The character is a man with a sister with a BRCA germline mutation. After this common introduction, the content of the messages becomes different.\n\nGroup 2 receives a family-referred narrative message in which the frame is similar to the previous message, but the character this time explains what are that the benefits for his family and why his decision to have a genetic test is important to them.', 'interventionNames': ['Behavioral: Message comparison']}

Interventions:
- {'type': 'BEHAVIORAL', 'name': 'Message comparison', 'description': 'Message comparison', 'armGroupLabels': ['First-person gain-framed family-referred messages', 'First-person gain-framed self-referred messages']}

Primary Outcomes:
- {'measure': 'Intention to undergo genetic testing', 'description': 'The intention of undergoing genetic testing is measured through three items evaluating the urge to engage the behavior. Example of item is: "In the next few months, do you have the intention of planning a genetic screening?". Response options are on a 5-point Likert scale.', 'timeFrame': '2-3 weeks after the intervention exposure'}

Please estimate the sample size based on the assumption: 
alpha lower than .05, power (1-B) = .70, 7 covariates
Sample size and power calculation
        Participants will be 264 males, relatives of women with BRCA1 and/or BRCA2 germline mutations who are patients of the Division of Cancer Prevention and Genetics at the European Institute of Oncology (IEO) in Milan. The IEO is a specialized Hospital and an internationally recognized Cancer Center located in Italy working on research, prevention, diagnosis, and treatment of cancer.
        The sample size is determined through an a priori power analysis using GPower 4.0 [51]. Among the imputed parameters it was chosen to include partial Î·2 = .05, alpha lower than .05, power d (1-B) = .70. Considering that Luszczynska et al. [52] found a Î·2 = .01, Î·2 = .05 is a prudential choice. Two groups, corresponding to the two experimental conditions of the study, and 7 covariates were included. The final estimated number of participants is 132, 66 in each group. It should be noted that changing the number of covariates does not change the total number of participants. As of the date of submission of this research plan for preregistration, the data have not yet been collected, created, or realized.