We thank Dr Knowles and colleagues for their interest in our editorial.1 The single gene locus responsible for cystic fibrosis was discovered more than 20 years ago, and the vast majority of patients with cystic fibrosis are still diagnosed on a functional measure, namely the sweat test. The issue for the diagnosis of Primary ciliary dyskinesia (PCD) is surely not what is available, but what is accurate. And in response to the proposed wager, we are always happy to take candy from babies!