28 CFR § 45.2: Disqualification arising from personal or political relationship [28 CFR PART 45—EMPLOYEE RESPONSIBILITIES]
(c) For the purposes of this section:
(2) Personal relationship
means a close and substantial connection of the type normally viewed as likely to induce partiality. An employee is presumed to have a personal relationship with his father, mother, brother, sister, child and spouse. Whether relationships (including friendships) of an employee to other persons or organizations are “personal” must be judged on an individual basis with due regard given to the subjective opinion of the employee.