Хм..
J.K. Rowling: It was a symbolic way of showing that he came from a loveless union – but of course, everything would have changed if Merope had survived and raised him herself and loved him.
The enchantment under which Tom Riddle fathered Voldemort is important because it shows coercion, and there can’t be many more prejudicial ways to enter the world than as the result of such a union.

Собственно, никакая амортенция для наблюдаемого эффекта не нужна. Гуглим "нарушение привязанности у сирот" и видим практически полную клиническую картину. Ну, с поправкой на гениальность, конечно, но в жизни редко бывает 1 в 1 как в учебнике.