def select_sex(sex) # :nodoc:
      given_sex = @fixed_sex ? @fixed_sex : sex
      raise ArgumentError, "Unknown sex #{given_sex}" unless GENDERS.include?(given_sex)
      given_sex == :random ? GENDERS[rand(2)] : given_sex
    end
def select_sex(sex) # :nodoc:
      given_sex = @fixed_sex ? @fixed_sex : sex
      raise ArgumentError, "Unknown sex #{given_sex}" unless GENDERS.include?(given_sex)
      given_sex == :random ? GENDERS[rand(2)] : given_sex
    end
:nodoc: