Are teeth hereditary?

In part, yes. Structural factors such as jaw size, tooth shape and alignment, and gum thickness are strongly influenced by heredity. Cavities and gum disease themselves, however, are bacterial conditions, so acquired factors such as brushing habits, diet, and regular check-ups largely determine the outcome. If cavities or gum disease ran in your family, it is worth paying extra attention to 1) a check-up every 6 months, 2) using floss and an interdental brush, and 3) controlling sugar intake.