Many reasons. Some women feel anxious because they have chronic, ongoing stress. Others might occasionally fear for safety of their family or themselves. There are many other reasons. Not all people, men or women, have a panic disorder. But if they have frequent or intense "attacks" it might help them to see a doctor, psychologist or religious leader.
Low blood sugar. Hypoglycemia or low blood sugar can cause panic attacks. When low blood sugar occurs, the body releases Adrenalin which is the "flight or fight" hormone. It makes you feel anxious. The treatment is to avoid sweets and artificial sweeteners, eat small amount of protein frequently, like every 2-2 1/2 hours. This usually takes care of the panic attacks if they are causes from low blood sugar.
Not quite sure. What your are asking. There is a medical explanation for panic attacks happening in men and in women, which has to do with the activation of the flight of fight response. But it is the same reason in men as in women.