Though there are no women in the novel, there is some perhaps underlying tension between Crusoe and Friday. Take, for example, this excerpt in which Crusoe is watching Friday sleep:
He was a comely handsome Fellow, perfectly well made; with straight strong Limbs, not too large; tall and well shap'd, and as I reckon, about twenty six Years of Age. He had a very good Countenance, not a fierce and surly Aspect; but seem'd to have something very manly in his Face, and yet he had all the Sweetness and Softness of an European in his Countenance too, especially when he smil'd. His Hair was long and black, not curl'd like Wool; his Forehaed very high, and large, and a great Vivacity and sparkling Sharpness in his Eyes. The Coulour of his Skin was not quite black, but very tawny; and yet not of an ugly yellow nauseous tawny, as the Brasilians, and Virginias, and other Natives of America are; but of bright kind of a dun olive Colour, that had in it something very agreeable; tho' not very easy to describe. (173)
Friday is Crusoe's subordinate and while there's probably no funny business between the two of them, there certainly is a sense of "ownership" in Crusoe description of him.
We also give it a PG rating because we know the young ones would be a bit afraid of the whole cannibalism thing. As are we.