Claim. Had Adam and Eve perfected love, married, and multiplied sinless children, they would have become the True Parents of humankind.
Elaboration. SMM states the counterfactual directly: God intended Adam and Eve to “reach perfection, marry, become established as the heavenly husband and wife, and live in the heavenly kingdom” (CSG 4.1 §7, Blessed Family 319). If they had not fallen, their children would have been born without sin and grown to perfection. Then, “by giving birth to such sinless children, Adam and Eve would have become the true father and true mother of humankind centering on God.” The title True Parents is therefore first an Adam-Eve office before it is a restoration title: the messianic role restores the parental position creation originally assigned to the first ancestors.
See also. true-parents, blessing