Cultural norms, from viewing a girl's role as wife and mother to not wanting girls to be taught by men, can be a significant barrier to girls attending school.

While education itself may be free, many schools require students to buy uniforms and supplies. Families with limited means often prioritize education for their sons.

Supplement: GlobalGoalsCast Podcast: Want to change the world? Educate girls.

Girls are often relied on for household chores, such as carrying water, leaving them little or no time to attend school.

Some girls miss school because they lack sanitary products during their periods. Still others stop going because of sexual harassment and fear of sexual assault.

A World Bank study found that across sub-Saharan Africa, each additional year of secondary school attendance significantly reduced the chance of girls being married before the age of 18.

The study also found that each additional year of secondary school reduced the likelihood of giving birth before the age of 18, contributing to safer pregnancies and healthier newborns.

According to UNESCO, if all women had a secondary education, 12 million children would be saved from stunted growth and malnutrition.

It is estimated that 153 million children worldwide, ranging from infants to teenagers, have lost one or both parents. If all mothers completed primary education, maternal deaths would be reduced by two-thirds, preventing many children from growing up as orphans.

Education narrows pay gaps and increases a woman’s chance of entering the workforce.