The researchers assessed over 1 million auctions from 2009 to 2012 and found that women sellers get fewer bids and lower final prices than men -- for the same products.
The gender bias was greatest for new products. In fact, it nearly disappeared for used items -- women make 97 cents for every dollar a man does.
The researchers said the lower gap seen with used products might be due to buyers unknowingly trusting women to give more accurate product descriptions.
The study, which looked at 429 of eBay's most popular items, found that even things like a seller's reputation score or the option to "buy it now" didn't mitigate the gender bias. Neither did the initial price or the product description.
The gender bias was even apparent in the resale of gift cards of equal value, which are objectively the exact same item.
eBay collaborated with the researchers of the study and provided them with access to the data.
The ecommerce site doesn't require sellers to display their gender. But researchers said that more than half of the time buyers were still able to correctly determine a seller's gender based on their username and the other items they sold.