“To all incredible women who strive for excellence” begins Serena Williams in an open letter about sexism and wage disparity between males and females in sports for Porter Magazine’s ‘Incredible Women of 2016’ issue, which The Guardian reprinted this week.

Serena Williams is one of the most amazing athletes in the world, people, and even she is not being paid as much for the same exact job as some of her male counterparts in U.S. Tennis.

Indeed, the New York Times reported in April that last year, Roger Federer received $731,000 to defend his title and play at the Western & Southern Open. At the same tournament, Serena received $495,000 for defending her respective title.

Seems ridiculous, doesn’t it?

Clearly, Serena thought so (as do I). Discussing the continued discrimination in professional sports, she said:

“When the subject of equal pay comes up, it frustrates me because I know firsthand that I, like you, have done the same work and made the same sacrifices as our male counterparts. I would never want my daughter to be paid less than my son for the same work. Nor would you.”

Regardless of the workplace you’re in, gender discrimination and unequal pay still abound.