Well the, ahem, meme [1] has been around for at least that long. I first heard similar sentiments with the release of reports that boys were doing poorly in schools, compared to girls, with some calls for boys-only schools. That was, what, about ten years ago?
WRT this specific issue, though, I'd put it at around a year/18 months ago that I first started hearing more and more calls for affirmative action for men in 'net conversations.
[1] I really hate 'meme theory' which has all the 'analytical subtlety of the cudgel in the hands of superbad guy at the end of donkey kong.'
"Be a scribe! Your body will be sleek, your hand will be soft. You are one who sits grandly in your house; your servants answer speedily; beer is poured copiously; all who see you rejoice in good cheer. Happy is the heart of him who writes; he is young each day."
--Ptahhotep, 4500 BCE