I assure you that you can't, despite being a genetic disease you will not be allowed, I have a permanent rejection letter that is called something else to prove it.
We have blood drives at my work all the time and I went to donate only to find out I couldnt which I actually was very embaressed about, at the time I was new at my work and not many knew I had CF and here she brings over this pink form for me saying I could never donate.
The lady explained that although its a genetic disease there was some fear or speculation that someone in an immune compromised state could be affected by our blood or possibly react or 'adopt' the mutated gene. Who knows whehter its true or whether she even explained it correctly but that is what I was told.