Fasting during Ramadan is obligatory, but is forbidden for several groups for whom it would be very dangerous and excessively problematic. These include pre-pubescent children, those with a medical condition such as diabetes, elderly people, and pregnant or breastfeeding women. Observing fasts is not permitted for menstruating women. Other individuals for whom it is considered acceptable not to fast are those who are ill or traveling. Missing fasts usually must be made up for soon afterward, although the exact requirements vary according to circumstance.