That is, altruism bestowed on kin is often "pure, true self-sacrifice" from the point of view of the organism. From the point of the view of the gene (not that genes literally have a point of view), this sort of altruism can be self-serving. In other words, dying while saving your family is definitely bad for you, but it may be good for your genes, since they stand a good chance of residing in your family members. For a fuller description of this logic of "kin selection," click here.