((a)) ** .—** The Secretary shall identify the birth defects of children of women Vietnam veterans that—

((1)) are associated with the service of those veterans in the Republic of Vietnam during the Vietnam era; and

((2)) result in permanent physical or mental disability.

((b)) ** .—**

((1)) The birth defects identified under subsection (a) may not include birth defects resulting from the following:

((A)) A familial disorder.

((B)) A birth-related injury.

((C)) A fetal or neonatal infirmity with well-established causes.

((2)) In any case where affirmative evidence establishes that a covered birth defect of a child of a woman Vietnam veteran results from a cause other than the active military, naval, or air service of that veteran in the Republic of Vietnam during the Vietnam era, no benefits or assistance may be provided the child under this subchapter.