An increasing number of family doctors are leaving the field for greener pastures and fewer young doctors replace them. South Florida has been hit hard by the trend, with dozens or even hundreds of primary-care doctors giving up their practices in recent years because of slow-growing income, increased business headaches, and unpredictable hours. To avoid a shortfall, the American Academy of Family Physicians estimates that Florida will need 63% more primary doctors within a decade, giving the state the third-highest gap in the nation.