Hereditary factors will play a rather large part in determining whether a child will develop allergies. Also, having at least one parent or sibling with allergies gives a child a 25% chance of developing allergies and this chance increases with every additional family member who has allergies. However, very specific allergies and certain types of reactions are not necessarily hereditary – so it is not very likely that the child will be allergic to the same exact things as the parent, nor will they always react in the same way. Children that are allergic to one substance are more likely, and susceptible, to developing allergies to other allergens as well. While heredity factors are very likely to be passed down to children – children who do not have any relatives with allergies are also able to develop them over time.