The capacity for magic tends to be, though not the area of expertise. That is not always the case, however. My family, for example.

[He brings his hands into the air, lines of light manifesting from his fingertips as he draws a tall figure with a staff.] Uncle Benistad -- the one who enchanted the cloak -- was a phenomenal magician. Primarily an elementalist, but he had vast talents in enchanting and abjuration, as well. Uncle Boris, on the other hand—

[He draws another figure, one taller and broader.] He had no skill at all. He could barely even activate the glyphs he crafted, if that.

[Finally, he adds a figure between them, one with his hair tied bad and holding a bow.]

My father, Kevin, had little proclivity for magic. Even if he did, it is unlikely he would have been a specialized healer, as I am.