Why do cystic fibrosis patients have barely any sperm come out?

Im 14 and have cf. i masturbate a lot but sometimes i wait and the same amount comes out. its only a few drops but i know it should be more. why does this happen and how can i make more come out because its embarrasing and i think it would feel better with more. id really appreciate your comments and info/opinions. thank you and please help me with thi.