(I can't type that sentence without hearing David Byrne in my head.)
Steven Chabot on Subject/Object asks how men in particular got into the library field.
In my case, it was more or less an accident, though in retrospect it seems inevitable that I ended up here. I remember when I started college at GSU, one of the first places on campus I started exploring was the library (the same library where I now work, incidentally). The OPAC was relatively new, I think: it was a series of terminals around the building with green monochrome text. I taught myself how to place holds by reading the help screens, and got scolded by the circulation staff for not going through them and filling out the paper form.
During and after college, I ended up in computer support jobs for several years. My turning point was getting a tech support job at the GSU Law Library in about 1992, my first library job. (This was a turning point in more ways than one, since I met my wife while working there.) The short version is that this led in a roundabout way to my first reference job, which was half reference work and half front-line tech support at the main GSU library. From there I moved to my reference and instruction job at Emory University's library, where I was really able to discover my path in library instruction and instructional technology. I stayed at Emory for seven years. My great co-workers at GSU and Emory over the years inspired me to get my MLIS, just in time to land my current gig.
In Steven's post he seems to be looking for answers to questions about gender in librarianship, and I'm not sure I've provided any useful data points. But I've seen this question about career paths come up once or twice before in the biblioblogobiosphere and have never gotten around to posting about it.