A claimant will have the relationship of grandchild or stepgrandchild of an employee, or the grandchild or stepgrandchild of an employee's spouse, and be considered a child for annuity purposes if the requirements in both paragraph (a) and either paragraph (b) or (c) of this section are met.

(a) The claimant is the natural child, adopted child, or stepchild of a child of an employee, or of a child of the employee's spouse as defined in this subpart;

(b) The claimant's natural or adoptive parents are deceased or are disabled, as defined in section 223(d) of the Social Security Act, in the month in which—

(1) The employee, who is entitled to an age and service or disability annuity, under the Railroad Retirement Act, would also be entitled to an age benefit under section 202(a) of the Social Security Act or a disability benefit under section 223 of the Social Security Act, if his or her railroad compensation were considered wages under that Act; or

(2) The employee dies; or

(3) The employee's period of disability begins, if the employee has a period of disability which continues until he or she could be entitled to a social security benefit as described in paragraph (b)(1) of this section or until he or she dies.

(c) The claimant was legally adopted in the United States by the employee's widow(er) after the employee's death, and the claimant's natural or adoptive parent or stepparent was not living in the employee's household and making regular contributions to the claimant's support at the time the employee died.