I too ride through a couple of "rough spots" and have often wondered about personal safety. I am 5'10", 215lb male and I worry about it, and so should everyone else. Male or female, you're no match for someone who ambushes you or is brandishing a weapon. That being said, I wouldn't be paranoid about it. Keep your eyes and ears open, vary your route (I have about 4 different commute routes), avoid riding at night.