The employee's natural child, as defined in §222.32, is considered to be dependent upon the employee. However, if the child is legally adopted by someone else during the employee's lifetime and, after the adoption, a child's annuity or other annuity or annuity increase is applied for on the basis of the employee's earnings record and the relationship of the child to the employee, the child will be considered dependent upon the employee (the natural parent) only if he or she was either living with the employee or the employee was contributing to the child's support when either:

(a) A spouse's annuity begins; or

(b) The employee's annuity can be increased under the social security overall minimum provision; or

(c) The employee dies; or

(d) If the employee had a period of disability which lasted until he or she could have become entitled to an age or disability benefit under the Social Security Act (treating the employee's railroad compensation as wages under that Act), at the beginning of the period of disability or at the time the employee could have become entitled to the benefit.