The allele for cystic fibrosis is recessive. What does this mean?

The recessive nature of the cystic fibrosis allele means that an individual must inherit two copies of the allele (one from each parent) to express the condition. If a person has only one copy of the cystic fibrosis allele and one normal allele, they will be a carrier but will not exhibit symptoms of the disease. This inheritance pattern affects how the disease is passed on in families, with carriers having a 25% chance of having an affected child if both parents are carriers.