I heard an interesting comment by a caller into "Radio Times with Marty Moss-Coane" (this is a show produced in the Philadelphia areas by WHYY, a local NPR affiliate). Audio of show here.
The caller remarked that she was tired of suble sexism of the media in its repeated references to "Mrs" Clinton and "Senator" Obama -- often in the same sentence.
I thought I'd put that unsuspecting caller to the test and run the numbers against Dow Jones Insight. It seems that the caller's perception of bias might be just that -- perceived.
In the past two years of articles from more than 6,000 mainstream media sources, we found 89,540 references to one of the following: Mr. Obama, Mrs. Clinton, Sen. Obama or Sen. Clinton. There were indeed more raw mentions of "Mrs. Clinton" than there were of "Mr. Obama". But there were also more total mentions of Clinton than there were of Obama.
Furthermore, if you compare the relative percentages of "mrs/mr" to "senator" you see that 29% of all mentions of either "Senator" or "Mrs" Clinton used the term "Mrs. Clinton" while 35% of all mentions of either "Senator" or "Mr" Obama referred to him as "Mr Obama."
So perhaps the media going out of its way just a little NOT to refer to Clinton as "Mrs."
When we dive deeper and just look at paragraphs where one title is used with a mismatch to the other, we see 69 paragraphs in two years where there was a mention of "Mrs. Clinton" and "Sen. Obama." While there were 99 mentioning "Sen Clinton" and "Mr. Obama." But to be clear, these 168 mentions are a trifle compared to the tens of thousands of articles mentioning them.
This shows clearly there has been no mainstream media bias in treating the two candidates differently because of their genders, at least in the use of courtesy titles.