I have a question to all the women out there. I am 20 years old and I do not get regular periods. My doctors have never asked about my periods and they actually have never even asked if I started getting periods ever! I have gone through a childrens and an adult clinic and neither of them have ever asked about it. I am worried about the irregular periods because I have heard that if you aren't producing enough estrogen to have a regular period you are more likely to develop osteoperosis. Have any of you guys had this problem and what did you do about it? Also have you heard anything about the osteoperosis and no periods and what does your doc say? I am going to my clinic in a few months and will ask then, but I just want to hear from some of you. Oh and although I am thin I am heavier than my sister (NO CF) and she gets regular periods so I don't think it is the weight issue...but then again I have no idea...Thanks for any advice!