For people with CRMS/CFSPID who have 2 identified CFTR variants, determining if the variants reside within the same copy (in cis) or different copies (in trans) of CFTR is achieved through the genetic testing of at least 1 first-degree relative, which is referred to as “phasing.” CFTR variants in cis can lead to diagnosis of CF carrier instead of CRMS/CFSPID,21,24 which bears health and reproductive implications for the individual and family members. Here, CFTR is linked to cystic fibrosis.