**Core Concept**
Cystic fibrosis (CF) is a genetic disorder characterized by abnormal chloride ion transport across epithelial cells, leading to thickened mucus production and various systemic complications. The disease is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, affecting chloride channel function and resulting in a range of pulmonary, gastrointestinal, and reproductive manifestations.

**Why the Correct Answer is Right**
The correct answer is a clinical feature not typically associated with cystic fibrosis. Cystic fibrosis patients often exhibit respiratory symptoms due to chronic pulmonary infections and inflammation, including **recurrent respiratory infections** and **persistent cough**. Gastrointestinal manifestations, such as **meconium ileus** in newborns and **malabsorption** in older children and adults, are also characteristic. Additionally, reproductive issues, such as **infertility** in males due to vas deferens agenesis, are common.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because cystic fibrosis patients often have **pancreatic insufficiency**, leading to malabsorption of fat-soluble vitamins and nutrients.
* **Option B:** This option is incorrect because cystic fibrosis patients are at increased risk of **diabetes mellitus**, particularly due to pancreatic islet cell dysfunction.
* **Option C:** This option is incorrect because cystic fibrosis patients often have **short stature**, likely due to malabsorption, pancreatic insufficiency, and chronic inflammation.

**Clinical Pearl / High-Yield Fact**
Cystic fibrosis patients often have a **salt-split sweat test**, which involves collecting a sweat sample from the forearm and analyzing it for chloride ion concentration. Elevated chloride levels confirm the diagnosis.

**Correct Answer:** D