Personally I think it's just coincidence. Maybe it has to do with the kind of image it would send for a guy to be a "softie" for food animals?
Either way, I'm vegetarian and plan on becoming vegan when I move out, simply because it's difficult enough to be vegetarian when my parents are both meat lovers
I second what CatandDiallo said, there's a difference between vegan and vegetarian. Vegan means no meats obviously, and also no dairy or eggs, etc. Vegetarian is basically nothing that would directly kill or harm the animal involved (so no meats or meat broths, and no hides/pelts).
If you ask me, it's a lot easier to do vegetarian first, get used to it (it's been 5 years for me and I hardly even think about it anymore - I know which places have vegetarian-friendly foods, and I know all the ins and outs of vegetarian food substitution). That way you can see if you can do that while keeping a good nutrient balance, and then make the progression to vegan. It'll be a seemingly tiny step after you've been vegetarian successfully.