I have gotten the answer from another thread. It was the New Hugo Award Winners Vol. 2 edited by Isaac Asimov. The story itself is "Eye for Eye" by Orson Scott Card, which won the novella award in 1988.
Mick Winger has an unusual gift and with it has accidentally killed several people. When Mick gets angry at people, his power manifests itself by launching an attack upon them by giving them cancer, leukemia or related terminal illnesses. If made angry enough, his anger can outright kill the victim.
Eventually he is led back to his birth parents, who are members of a mysterious, secluded colony. Talking to his parents, who also possess his ability, he learns he is far more powerful than they or probably anyone else at the colony. Mick learns that what he sees as "sparks" his family only sees as dust; he even begins to realize that he can see when people are lying. After being brought to the villages Patriarch, Papa Lem, Mick learns the intent of the colony and how they operate. Mick then refuses to "spread his seed" with the daughter of Papa Lem and returns to his parents' house for the night. During the night, Mick is attacked by an agent of Papa Lem and others from the village. Mick ends up killing his father and setting fire to the village while at the same time learning new extents to his abilities.