Elementary my dear.. Its all about PAY vs. type of work and "BS you might have to put up with" ratio.
1. Males generally speaking aren't even close to being interested in bedside nursing. Most males wouldn't want to get near the job.
2. You will * virtually * always find males congregating where the money is in *virtually* field. Law? Males dominate patent law (very hard to get into, pays well, engineering degree required to sit for the exam); A male will generally take a job with a firm that makes millions settling tort/vicarious liability cases (and the like) WAY before even considering family law. Medicine? Notice how males generally don't want ped., or general practice, etc.? Hmmm.. but the cut throat competition between males for ortho and other nice paying specialties are almost proverb. Aviation? Most males wouldn't THINK of serving you food on an airplane, they're more apt to be pilots. <~~ I'm merely stating fact.. please don't read into it and tell me that your sister's friend's niece flies for Delta.
3. Ok, now we get to nursing.... CRNA is arguably the highest paid nursing position on the planet. Now if you take 100 Type A, heterosexual males and ask them which they'd consider.. ICU, OR, CRNA or bedside nursing.. I can assure you almost NON would want the latter.
I've said it 100 times and I'll say it again... if bedside nurses got paid $240,000.. then you'd see a LOT more men entering the field. But in the mind(s) of most men, its not worth the trouble to play "nurse-maid" for $40,000 per annum, when one can be an engineer (even with only a 4yr CE or EE degree) and make $20k per annum more, while working in the air conditioning! OR make $56-70k working in a outpatient clinic as a Physician Asssistant or Nurse practitioner.
Bottom line... "low pay = the boys stay away" (generally speaking)