I noticed a gender focus : why are so many Japanese MEN refusing to leave their rooms?

I found a research report on the topic which basically seems to say that Hikikomori women are probably labeled as "Parasite Singles" rather than Hikikomori, but if the two sets of youth were considered as one, the distribution by gender would be closer to 50:50 rather than the impression that the media serves to give that is is almost always a man : http://towakudai.blogs.com/Hikikomori_as_Gendered_Issue.pdf