It has been reported that only a small proportion of funds raised during "A Crucial Catch", the league's month-long campaign to support breast cancer research through the sale of pink merchandise and memorabilia, will actually go to help breast cancer research.

The NFL's campaign, which aims to increase awareness of the need for annual breast cancer screenings "especially for women who are 40 or older", runs throughout October and sees many players wearing items of pink equipment during games. All such apparel and a number of other items, including pink game balls, will later be auctioned in aid of the American Cancer Society's Community Health Advocates National Grants for Empowerment (CHANGE) programme. The league also gives fans the chance to donate $10 to the American Cancer Society, by sending a special "NFLPINK" text message.

However, citing data obtained from the NFL, Darren Rovell of ESPN tweeted: "On pink gear, the NFL says it takes a 25% royalty from the wholesale price (1/2 retail), donates 90% of royalty to American Cancer Society."

At Business Insider, Cork Gaines wrote: "In other words, for every $100 in pink merchandise sold, $12.50 goes to the NFL. Of that, $11.25 goes to the American Cancer Society (ACS) and the NFL keeps the rest." Gaines added: "The remaining money is then divided up by the company that makes the merchandise (37.5%) and the company that sells the merchandise (50.0%), which is often the NFL and the individual teams."

Most pink NFL merchandise is sold through the NFL's online store, making the NFL the company which sells the merchandise and thus receives 50% of the money received.

A Steelers fan supports Breast Cancer Awareness Month. Photo: Chris Szagola/Zuma Press/Corbis

Writing for the Los Angeles Times, Patt Morrison asked: "What does it really mean, that anodyne marketing phrase, 'A portion of the proceeds from this product will be donated to help fight breast cancer'?" Morrison also discussed claims that the NFL's efforts to promote breast cancer research are also aimed at capturing a female audience.

The NFL has not yet commented on the issue.

Efforts to raise money for breast cancer research continue outside the NFL. This weekend, the University of Oregon Ducks will wear pink helmets for their game against Washington State. They will also wear pink cleats, socks and gloves, in an effort to raise money for the Kay Yow Cancer Fund, which is named for a North Carolina State women's basketball coach who died from the disease in 2009. Twenty-five of the pink helmets will be auctioned.