hi.. it is very unfortunate but the vas deferen(the tube in which the semen is brought from the testicles to the penis)is not present in about 97% of males with CF, so the answer is 97% of males with CF cannot produce babies. HOWEVER, I dont know if semen is still produced in the testicles so maybe there is options such as removing produced semen from the testicles and injecting it into the women. Depends on how one would feel about doing this. Hope this helps. I found this information out because I am a CF female and I wanted to know if I could reproduce and my CF clinic gave me all the facts.