Besides your mother or grandma (who may no longer have this problem), have you lived with other females? Have you had to deal with mood swings, attitudes, unnecessary lip biting...do any of these ring a bell and do they all have some sort of correlation with what time of the month it is?
If they do, and you would like a heads up as to when you should put your guards up, there is a free site that gives you just that. It is called PMSBuddy.com.
I personally think it is quite ridiculous and think its just another excuse for women who have attitudes to be treated differently. I don't think it is any one's business when I have my monthly hormonal changes going on. I shouldn't be treated differently, nor shall people feel they should interact with me in another way.
Its the facts of life. Women have been blessed with the ability to bear children and have been scorned with this monthly reminder of what happens when you're not having them.
I do want to sign up though to see what the service actually entails - again, its free :)