All the analysis relies on numbers released by the campaigns, since they include small-dollar donors that the candidates are not required to itemize on federal filings.
Symone Sanders, a spokeswoman for the Sanders campaign, said the number shows "the grassroots enthusiasm for Senator Sanders is unmatched by any other candidate. The fact that so many women have decided to donate to the senator's campaign says that his policies and record are indeed resonating with women across the country."
But the higher number of women donors for Sanders is due to the fact that he has an overall larger number of individual donors than Clinton, a fact that he frequently points out on the campaign trail, noting that he refuses to take money from corporations and super PACs.
Sanders claims more than 689,000 individual donors to nearly 400,000 for Clinton. That means that the former secretary of state still can brag that a higher percentage of her contributors are women -- 60 percent versus 44 percent for Sanders.
"We are honored by the support Hillary has received from the hundreds of thousands of women who have donated money to her campaign and make up more than 60 percent of our donors, as well as the tens thousands of volunteers who are donating their time and energy across the country as part of this historic campaign," Kristina Schake, a campaign spokeswoman, said Tuesday.
Clinton, who in 2008 played down her gender, this time is unabashedly asking voters to help her make history by becoming the first woman elected to the White House. Starting last summer, after its first two and half months of fundraising, her campaign has noted to news media that women made up more than 60 percent of her donor base.
The line is also used in fundraising pitches to women, as in an invitation to an upcoming fundraiser with female Democratic senators next week: "Women are the cornerstone of this campaign. I’m proud that 60 percent of our donors are women, and even prouder that we’re building a country where we can finally say to all our daughters, 'Yes, you can be anything you want when you grow up, even President of the United States.'"
During the Democratic candidates' debate earlier this month, Clinton again invoked the stat when Sanders said that "Wall Street been a major -- the major campaign contributor to Hillary Clinton."
Clinton responded, "not only do I have hundreds of thousands of donors, most of them small. And I'm very proud that for the first time a majority of my donors are women, 60 percent."
It is not clear why the Sanders campaign is challenging Clinton's fundraising prowess with women now. Several weeks ago the two camps butted heads over allegations of sexism after an exchange between the two over gun control during the first debate. Sanders used the term "shouting" to characterize the long-running argument between opposing sides on the issue. The next day, Clinton said, while speaking at a Democratic women's political forum, "When women talk, some people think we're shouting."
Sanders vehemently denied that his comment was sexist and when the issue came up at the second debate earlier this month, he said: "The problem is ... people all over this country -- not you, Secretary Clinton -- are shouting at each other. And what we need to do is bring people together to work on the agreement where there is broad consensus and that's what I intend to do."
Sanders's fundraising efforts were big news at the end of September because he raised $26 million, almost as much as Clinton's $28 million, for the third quarter reporting period.
Clinton still leads Sanders in overall fundraising, $76.5 million to $41.3 million.