 Why does Roger speculate there are more females than males in the fourth dimension environment?
Dana stood almost in the center of the room, carmine-tipped fingers clasped beneath the swell of her breasts. Somehow it brings things closer...." We seem to be in a universe of different properties as well as different dimensions. "But I'll settle for the fourth—a fourth dimension in space, if that makes scientific sense, because we don't seem to have moved in time. "They pass through their gateway to Earth at considerable danger and, probably, expense of some kind. "In the one instance, we're the hunters, the breeders, the trophy collectors. As in all of this strange universe, excepting the dome-cages in which the captives were held, the training hall followed no rules of three-dimensional space.
 The ones controlling the environment have a more challenging time bringing males through the fourth dimension.
 Roger believes that the ones controlling the environment are running a breeding program to raise children who will eventually grow up to be body snatchers.  The ones controlling the environment have a more challenging time bringing males through the fourth dimension.  The ones controlling the environment are overwhelmingly male, heterosexual, and desirous of sex with women.  Roger does not make any kind of guess as to why he is in the minority among the women of his "harem."