(3) Nothing contained in sub- section (1) or sub- section (2) shall be construed as conferring upon any child of a marriage which is null and void or which Is annulled by a decree of nullity under section 12, any rights in or to the property of any person, other than the parents, in any case where, but for the passing of this Act, such child would have been incapable of possessing or acquiring any such rights by reason of his not being the legitimate child of his parents.]