This is, of course, not the first federal election in which misogyny has been an issue. Previous leaders such as Gough Whitlam and Paul Keating were subjected to coded attacks on their masculinity on the basis that they were giving too much power to women in government.

But there has been nothing like this before. With a Prime Minister who is not just a woman, but a childless atheist as well, the Opposition and its media allies have had a field day. Complementary lines of attack suggest that men who support Julia Gillard have thereby been emasculated, and that the Prime Minister herself does not deserve to be regarded as a “real woman” — “real women” being the ones who know their place, which is firmly under the thumb of the “real men”.

Do these attacks really resonate with the electorate? One might think not, since surveys generally show that Australians have pretty relaxed attitudes on gender issues. Polls have shown a consistent “gender gap” in voting intention, but no one admits to voting against Labor solely from dislike of a female leader.

On the other hand, survey data gets less and less reliable as issues become more personal, and there isn’t much that’s more personal than s-x. Could misogyny be a big sleeper issue in this election?

Some readers may remember the “Bradley effect”, which was much discussed during the 2008 presidential campaign in the United States. Named for a 1982 election for governor of California, the theory is that many white voters, although intending to vote against a black candidate (whether for racist motives or not), will not admit that to opinion pollsters due to social desirability bias, leading the black candidate to underperform relative to their poll results.

Nate Silver at fivethirtyeight.com has recently coined the term “Broadus effect” to refer to a new version of the same phenomenon, where support for marijuana legalisation is higher in automated polls than in those involving a human operator.

Silver suggests that since marijuana still carries a social stigma, some voters are concealing their support for fear of disapproval.

It’s possible that we will see something similar in Australia — polls may be understating the Coalition vote because some respondents are afraid of being seen as s-xist for opposing a female leader, regardless of their actual reasons.

But it’s also possible that social pressure is stronger the other way: that there are male voters who are unwilling to admit to supporting Gillard for fear of the disapproval of their less-enlightened brethren.

Certainly the tone of much of the media suggests that pressure is very real. If so, the polls will be overstating the Coalition’s support, not understating it.

Either is possible — or the two effects may roughly cancel out, or they may both be too small to worry about. Polling is an inexact science; we don’t know, and we may never know. But August 21 should give us some ideas.