A friend has 2 dc, one of which has a cf diagnosis. She bfed him till he weaned self (near 3 i think). They werent aware of cf till he was nearly 1 iirc. They have a 6 week old now and there is 4 years between the children. She is thinking of swapping to formula as she thinks it isnt important to bfeed as dc2 is clear of cf. She also wants to continue to give dc1 the same level of input as he had pre dc2. I think its a real shame, and if anything i have bfed dc2 longer than dc1 because of experience.