I think Dr. Beard is right--the biggest barrier is hostile work/school environments re: pumping. The policy might be all PC on paper, but employees and bosses can make it very difficult. (And women can be especially cruel to each other over this issue--it is definitely one where emotions run high.)
This is most apparent to me for women in medicine--probably the LEAST friendly environment when it comes to breastfeeding and pumping, especially during training. It is almost impossible to continue pumping when working 80 hours/week, and I think sometimes women physicians feel so vulnerable to judgment if they have to quit or cut back because of that. I think it makes us extra-sensitive to "judging" women or "forcing" breastfeeding on them when we are so keenly aware of the obstacles. At the same time, we might be withholding support, knowledge and advice from patients who need it, simply because of our own raw feelings or perceived lack of personal experience. Really it's the system that has to be changed, and we are caught in the crosshairs.
This is an interesting post with a good discussion following:
http://www.mothersinmedicine.com/2010/01/breastmilk-vs-formula-epic-battle.htmlI'm interested to hear what others have to say!