Following this, Herbert becomes pre-occupied with excrement, which Freud and Herbert's father help him to associate with the birth of babies. The carts and omnibuses are associated with the boxes which, according to the theory of reproduction that Herbert has been given, storks use to bring new babies. Herbert fears the arrival of more babies as this will further reduce the attention he receives from his mother, and expresses the wish that his baby sister should die. He also expresses the wish to have children of his own (with his mother) with his father elevated to the role of grandfather.