There are traditionally female friendly specialties like OB and peds. OB has a malignant lifestyle just like surgery. The real question is what do you want to do and where do you want to do it. If you enjoy what you do than the hours do not matter as much. NYC, Chicago, LA etc. you may run into a few older docs that have a prejudice re: women surgeons but most patients won't care so long as you dress the part and seem halfway competent.
As an aside.....When I was doing an EMT rotation in a hospital, several patients just assumed I was a doctor because I had a white coat, stethscope and I was Caucasian. In that particular hospital, most of the doctors in the ED (about 90%) were white, most of the nurses were African-American or Latino and the medics were a mixed rag tag lot. Patients do make assumptions but my experience (and perhaps this was because it was a big city hospital), there were a lot more stereotypes about race than gender.