The gender gap exists on eBay, according to the study. Getty The gender pay gap exists on eBay, too.

A study of 1.1 million eBay auctions between 2009 and 2012 showed that women earn considerably less than men for selling the exact same items. For new products sold on the auction site, women earned only 80 cents on every dollar that men earned, the study found.

However, the auctioning site was keen to distance itself from the study, saying it was not commissioned by eBay and adding that the company is "passionate about harnessing our platform to empower millions of people by leveling the playing field for them."

The study was published in the Science Advances journal earlier this month and was led by Dr. Tamar Kricheli-Katz, a sociologist at Tel Aviv University, and economist, Tali Regev. The pair were some of the first researchers to be allowed into eBay's offices in San Jose, California, according to Science Magazine.

The results might seem strange because eBay does not actually declare the genders of its sellers to its buyers. However, the scientists showed in a separate experiment that gender is very often discernible from information gathered from a quick look at the seller's profile — information like usernames and the items they sell give big clues (this is explained further below.) It's not clear how many users actually look at the profiles, however.

Speaking exclusively to Business Insider, the two researchers revealed the exact percentage difference between what women and men received for the same items over the 3-year period studied.

These are the items sold on eBay which created the biggest gender pay gaps:

7. Gift vouchers — Women earned 6.8% less than men for gift cards of identical value.

6. Golf balls — Women selling golf balls received 20% less than male sellers.

5. Invicta Pro Diver watches — Men selling these watches earned on average 20% more per watch than women sellers.

Amazon

4. IPod 1st generation — This iconic Apple relic generated 24% less income for women.

Flickr/kenfagerdotcom/

3. Printers — Printing devices earned a significant 30% more for men than women.

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2. Folding knives — Buyers were willing to pay 61% less to women sellers of knives like this.

Flickr / James Case

1. Nintendo Wii — Most shockingly, Nintendo Wiis went for 270% more money for men than women.

However, there were a few items for which women earned more than men. For example, Barbie dolls generated 16% more income for women.

In this Sept. 29, 2015, file photo, Barbie Fashionista Dolls from Mattel are displayed at the TTPM Holiday Showcase in New York. AP

Less predictably, women earned 20% more from pet food.

However, the differences did not equal out. The study says women earned 80 cents for every $1 a man earned on Ebay between 2009—12.

This is despite the women having a slightly higher average positive feedback rating on the site: 99.6% compared to 99.58% for men.

It seems the bias occurs because sellers' genders are discernible from their users profiles. In a separate study, the scientists asked 400 people to state the gender of 100 randomly-selected sellers, according to Science Magazine. Only 9% of the guesses were wrong and 56% were correct, while 35% were deemed un-guessable. So, more often than not, the gender of sellers could influence the final sale price.

The report is "a new addition to the growing body of evidence that gender inequality doesn't end when people go online," Benjamin Mako Hill, an internet academic at the University of Washington, told Science Magazine. "The fact that gender seems to lead to such a gap in eBay, where gender is such a relatively tiny signal, is striking."

The two scientists worked using data from eBay's labs. Katz told Business Insider: "They gave us the data in their labs and committed to give it to anyone who would want to replicate the results."

An eBay spokesperson sent this emailed statement:

This study, which was based on data from more than 4 years ago, was not conducted or commissioned by eBay. Today, 48% of our top US consumer sellers are female.

With regard to gender and the diversity of our marketplace more broadly, for 20 years eBay’s purpose has been to democratize commerce and create economic opportunity for people regardless of age, ethnicity, gender, ability, or geography. We are passionate about harnessing our platform to empower millions of people by leveling the playing field for them. We do not reveal the gender of our sellers, although they can choose to do that themselves. When our sellers succeed, eBay succeeds.