In 1971, the U.S. Congress declared August 26 as Women's Equality Day, according to the National Women's History Project. The day celebrates the passage of the 19th Amendment in 1920, which granted women the right to vote. Each year, the president is requested to issue a proclamation honoring this day around the country.

While much progress has been made since the amendment was passed, women are reminded every day that there is still a lot more work to be done before equality is fully reached. A new study conducted by financial services firm Merrill Lynch and research company Age Wave found that by retirement age, a woman may have earned as much as $1,055,000 less than her male counterpart over the course of her career.

Pay disparity and common workforce interruptions, like caring for a sick parent or starting a family, contribute to this gap. Merrill Lynch and Age Wave found that one out of three mothers who returned to work after caring for a child say they took on less demanding work that came with a lower paycheck. Additionally, 21 percent say they were paid less for the same work they did previously...