They are many reasons why women earn less than men. The main four involve "occupational segregation," the way women and men are steered toward different occupations. Girls, at a young age, are often encouraged to enter "soft" professions, such as education, while boys are routed into math or science-related fields.
A kindergarten teacher will never earn as much as a financier. Even when she adjusts her major, a female college graduate will get paid less than a man. From her first job, she can get locked into permanently lower pay. If she has children, the female is vulnerable to a pay cut because employers don't think female workers will be committed to their occupation.
Another side of the “motherhood penalty” is the impact felt by some women if they step away from work to care for children or family members. Leaving the workforce has lasting implications for a woman's salary and financial health.