Many people develop allergies simply through overexposure to allergens, especially when they are very young (though some are genetically predisposed to developing allergies). While there are many other risk factors, exposure to indoor allergens is now one of largest and yet one of the most preventable and controllable causes of allergic illness. The medical community has identified dust mite and pet allergens as posing the greatest risk for the development of allergies in the first place, continued suffering of those with allergic illness, and a component in the development of much more serious allergic diseases such as asthma and sinusitis.