Men and women have been voting differently in presidential elections for decades.

But could the gender gap be the deciding factor in this year's razor-thin race between Vice President Kamala Harris and former President Donald Trump?

The final ABC News/Ipsos poll before Election Day, released on Sunday, found the gender gap among all likely voters to be 16 points. Harris had a 11-point advantage among women, 53% to 42%, while Trump had a 5-point advantage among men, 50% to 45%.

A 538 analysis of national polling crosstabs in October from its most highly-rated pollsters found the average gender gap was slightly wider: 10 points for Harris among women and 9 points for Trump among men.

That is on par with historical norms. The gender gap has averaged 19 points in presidential exit polls since 1996.

Some observers, though, believe it could reach a new level in 2024.

"With a woman versus a man at the top of the ticket and with the prominence of the abortion issue in the wake of the Dobbs decision, we could have a historically large gender gap approaching a gender chasm this year," Whit Ayres, a longtime Republican pollster, told ABC News.

The formula to success for Harris would be to win women by more than she loses men. The reverse is true for Trump.

"When you're talking about dead heat races in seven swing states, anything could be the deciding factor," Ayres said.

Both campaigns try to turn the gap to their favor

Harris has made reproductive freedom a centerpiece of her White House bid. In recent weeks, she rallied with Beyoncé in front of tens of thousands in Texas on abortion rights, visited a doctor's office in battleground Michigan and deployed high-profile surrogates like Michelle Obama to talk about the impact on women's health after the fall of Roe v. Wade.

"I think you can't underestimate the power of the abortion issue," Celinda Lake, a veteran Democratic pollster, told ABC News.

That's especially true, Lake said, among younger women. Harris has an overwhelming lead (40 percentage points) among women ages 19 to 29 compared with Trump's 5-point advantage among men in that same age range, ABC News and Ipsos found.

"They are registered in record numbers but we have to make sure they all turn out to vote," Lake said of Gen Z women.

Harris' campaign has also done extensive outreach to men, including Black men, through her economic proposals. Polls earlier this fall showed support from Black men for Harris was eroding from President Joe Biden's numbers with the group, though Harris has appeared to regain ground. In the final ABC News/Ipsos poll, Harris had support from 76% of Black men (Biden won Black men by 79% in 2020) and 87% of Black women.

Trump, meanwhile, has focused on driving men to the polls, particularly younger and apolitical men who vote at lower rates than other groups.

Both Trump and his running mate, Ohio Sen. JD Vance, sat down with popular podcast host Joe Rogan. Trump's surrounded himself with hyper-masculine figures on the trail, including Elon Musk and Hulk Hogan. He's embodied a strongman persona and doubled down on authoritarian rhetoric.

White men and women have long been among the Republican Party's strongest constituencies. Trump is leading with white men by 13 points, according to the latest ABC News/Ipsos poll, and among non-college educated white men and women by roughly 30 points. And while he leads with white women, the largest voting bloc in the U.S., Trump is only edging out Harris by 4 points: 50% to 46%. (Trump won white women by 11 points in 2020 against Biden.)

Trump has also ramped up efforts to court Hispanic voters, a demographic that has its own significant gender divide, more this campaign than in his previous presidential bids. The ABC News/Ipsos survey found an average of 55% support for Harris among Hispanic likely voters and 41% for Trump. (Biden won Hispanic people by 33 points in 2020, according to the ABC News exit poll.)

"I think Trump is trying to drive up his vote among men," said Ayres. "I haven't seen a whole lot of outreach to women."

The former president's recent messaging to women is that he will "protect" them "whether the women like it or not" -- a line that went against the guidance of advisers, whom he claimed had called the statement "very inappropriate." Harris quickly seized on the comment as "offensive to everybody."

Turnout will be key

More than 75 million Americans have voted early, according to the University of Florida's Election Lab.

Women are outpacing men in early vote turnout, the data shows, 54% to 43.6% as of Sunday. That is in line with past elections, including in 2020 when women made up 53% of the electorate.

Tom Bonier, a Democratic strategist and CEO of the data firm TargetSmart, said one notable takeaway is that women are voting early at higher rates than men by "pretty substantial margins in every battleground state except Nevada."

It is unknown which candidate early voters are casting their ballots for and unlike in 2020, when Trump discouraged mail-in voting, more Republicans are voting early this year.

But Democrats see optimism in the margins.

"There's just simply more women in the electorate and they turn out to vote more," said Elaine Kamarck, a senior fellow at the Brookings Institution who worked on several presidential campaigns. "If you add in their preference for Harris over Trump, this should be very good news for Harris."

538's Mary Radcliffe contributed to this report.