A child shall be deemed dependent upon his father or adopting father or his mother or adopting mother at the time specified in paragraph (1)(C) of this subsection unless, at such time, such individual was not living with or contributing to the support of such child and—

(A) such child is neither the legitimate nor adopted child of such individual, or

(B) such child has been adopted by some other individual.

For purposes of this paragraph, a child deemed to be a child of a fully or currently insured individual pursuant to section 416(h)(2)(B) or section 416(h)(3) of this title shall be deemed to be the legitimate child of such individual.