According to US census information from 2019, women make only $0.81 for every dollar a man makes.
However, gender isn't the only root cause behind pay disparity, as authors around the world are trying to show as part of a candid new movement.
A number of writers have taken to social media to share the amount they have been paid for their work, to highlight the disparity between white and black authors.
Black fantasy author LL McKinney this week started the #publishingpaidme hashtag, which asks authors to share the advances – an upfront payment for their books – they were paid by their publishers.
The initiative comes as widespread protests highlighting racial injustices are held around the globe in the wake of George Floyd's death in police custody.
“Come on, white authors. Use the hashtag and share what you got for your books,” McKinney wrote on Twitter. “Debuts as well. Let’s go.”
The author added that the movement is meant to highlight “the disparity between what’s paid to non-Black authors vs. Black authors. Not PoC [people of colour]. There’s a reason for that, especially in the context of this moment.”
A number of prominent writers were among those to reply to the thread, including black feminist author Roxane Gay, who revealed she was paid $12,500 (Dh45,900) for An Untamed State, $15,000 for Bad Feminist, $100,000 for Hunger, $150,000 for Year I Learned Everything and "a significant jump" for her next two books.
“The discrepancy along racial lines is very real. Keep your day job,” wrote Gay on Twitter. “I like my publishers quite a lot but this is why all those corporate statements about diversity are nonsense. A little Instagram post doesn’t make up for racial disparities in everything else.”
White male novelist Matt Haig, meanwhile, revealed that while the advance on his first book was £5,000 (Dh23,200), the sums had increased to £600,000 by the time he penned his 10th book.
Advances are payments deducted from future royalties, and therefore based on how well publishers believe a book will sell.
White science-fiction author John Scalzidivulged revealed that while he has been paid as little as $2,000, his most recent deal – for a series of 13 titles – was $3.4 million, which works out at roughly $260,000 per book.
In comparison, black sci-fi author NK Jemisin revealed she received $25,000 apiece for each book in her Broken Earth trilogy, each of which won a Hugo Award, a prize for writing in the sci-fi and fantasy genre.
Jesmyn Ward, a black American novelist, added that she was paid $20,000 for her National Book Award-winning fiction Salvage the Bones.
"Even after Salvage the Bones won the NBA, my publishing company did not want to give me 100k for my next novel. My agent and I fought and fought before we wrestled our way to that number," she tweeted.
Malorie Blackman, a black British writer and former Children's Laureate, said she had "never in my life received anything like the sums being posted by some white authors".
However, the author urged black writers to not stop putting pen to paper.
"We might not win at this game but to not play is to definitely lose. If we give up, nothing changes. Our stories are worth telling and need telling."