President Barack Obama and his Republican challenger, former Massachusetts Governor Mitt Romney, are almost evenly tied among likely American voters, according to polls.
But breaking down the numbers by sex tells a different story. Polls show Obama leads women by several percentage points, while Romney enjoys a similar lead among men.
Democratic presidential candidates have performed better among women than men for the past few decades. And this election cycle, the Republican Party has drifted rightwards on issues like birth control and abortion, and a number of Republicans have made controversial comments about women and rape.
"Even when life begins in that horrible situation of rape, that is something that God intended to happen."
- Indiana Senate candidate Richard Mourdock
For example, on October 23, Richard Mourdock - a Republican running for a Senate seat in Indiana - remarked during a debate that "even when life begins in that horrible situation of rape, that is something that God intended to happen".
The comments created a political firestorm, with a spokeswoman for President Obama calling his comments "outrageous and demeaning to women", and Romney's camp emphasising that the Republican presidential nominee "disagrees with Richard Mourdock's comments".
For his part, Mourdock says his original statement had been distorted. "I spoke from my heart, I spoke with my principle, I spoke from my faith, and if others want to twist my words and use them against me, again, that's what's wrong with Washington today," he explained.
'Binders full of women'
Mourdock's comments echoed those made two months earlier by Todd Akin, a Republican congressman running for a Senate seat in Missouri. Akin said that women's bodies have defenses against pregnancy if they are the victims of what he called "legitimate rape". Although Akin came under heavy fire from members of both parties for his comments, he refused to back out of the race.
Akin later accused his Democratic opponent, Senator Claire McCaskill, of not acting as "ladylike" as she had in her previous election.
Romney himself has received flak for what critics say are his ham-handed attempts to appeal to female voters. In the second presidential debate between him and Obama, Romney boasted that as governor of Massachusetts, he wanted to hire more women in his cabinet, and that women's groups brought him "binders full of women" - a phrase that immediately drew ridicule on social media websites.
Democrats have tried to take advantage of conservatives' statements on women. For instance, after conservative radio personality Rush Limbaugh repeatedly described a law student who had testified before Congress about birth control as a "slut" and a "whore", the Democrats invited her to speak at the party's national convention this September.
The ideological gap
But the gender gap is likely driven not so much by controversial comments and gaffes as by real ideological gaps between the major political parties - straits that have widened in recent years.
Rape comment causes rage in the US
Former Republican presidents such as Richard Nixon and George H W Bush were strong proponents of family planning. In recent years, though, pro-life Republicans have pushed hard to cut or eliminate state funding for Planned Parenthood, a family planning programme that provides contraceptives and also performs abortions.
Many Republican politicians have also opposed a provision in Obama's health-care plan - colloquially known as “Obamacare” - that requires most health insurance plans to provide birth control free of charge.
These stances are unlikely to curry favour among women voters, as a large number of them say abortion is the most important issue to them in this election.
And it’s not just reproductive issues that cause a partisan divide between female and male voters. Susan Carroll, a professor of political science at Rutgers University, notes that “women and men have had a long-standing … difference in terms of opinion about on issues of war and peace, particularly when the question has anything to do with military intervention”. Republicans have traditionally been more hawkish than Democrats.
Debbie Walsh, director of the Center for American Women and Politics, adds that women and men often have different philosophies on what role government should play. Women, who on average make less money than men, “see themselves as more economically vulnerable," she says. "They see themselves as needing, at some point, some aspect of that social safety net that government supports.” Democratic politicians tend to back government spending on social programmes more than Republicans.
A 'man problem'?
But if Romney and the Republicans have a “woman problem”, as some have argued, can it therefore be said that Obama has a “man problem”?
If only men were allowed to vote in the United States, the New York Times' Nate Silver predicted, Romney would almost certainly cruise to victory. Obama would win just a handful of true-blue Democratic states, like California, New York, and Illinois.
Few issues discussed in this election cycle specifically concern men. One poll released by Gallup, however, found that men are more likely than women to list the federal budget deficit as the most important issue facing the country. And surveys show that when it comes to the deficit, voters trust Romney more than Obama.
Despite these differences, Karen O’Connor, founder of the Women and Politics Institute at American University, points out that in this election the gender gap - the number of percentage points by which women favour Obama plus the number of points by which men favour Romney - could end up being smaller than in past elections.
Polls conducted over the past week show the gap averaging about 12 percentage points - smaller, for instance, than in the 2000 presidential election, when the gap was 20 points.
O’Connor also advises some scepticism about the polling data. “There is way too much polling ... using much smaller samples - of 500, in many cases. If you do the math, it probably means 260 women polled.”
Not only do women make up half of the US population - they’re also more likely to vote than men. Walsh says that in the 2010 midterm elections, 10 million more women voted than men.
“That is why this gender gap is so important to both candidates," she told Al Jazeera. "On the Republican side they want to narrow that gap as much as they possibly can, on the Democratic side to try to widen that as much as they possibly can.”
Follow Sam Bollier on Twitter: @SamBollier