The amount of dietary iron a person requires varies depending on age, gender and other factor such as activity level and pregnancy, according to WebMD. An average adult woman requires about 18 milligrams of iron per day, while an average adult man may only need 8 milligrams.
In general, babies and toddlers require proportionally more iron than adults because their bodies are still in the process of growing. Regardless of gender, children between the ages of 4 and 8 require about 10 milligrams of iron per day, explains WebMD and the Office on Women's Health. Between ages 9 and 13, this amount is reduced to about 8 milligrams. Pregnant women require substantially more iron than an average adult. A pregnant woman between the ages of 14 and 50 should consume 27 milligrams of iron daily, notes the Office on Women's Health.