Note that correspondence audits are triggered by the numbers not matching. There is basically a 100% chance you did something wrong in filing your return, or that somebody you're intertwined with did something wrong in theirs. (Although this doesn't always mean your tax bill changes, it can be triggered by mislabeling something.)
Thus if there is anything to be done here it's figure out why they fuck up so much more. The IRS isn't discriminating. (Note that the somebody-else possibility isn't a large part of the effect--if you both claim it's going to show up as questioning both returns and the single male rate is a lot higher than the single female rate. Note, also, that we don't see the pattern with joint EITC filings.)