**Question:** All are causes of Gynaecomastia, except

A. Hormonal imbalances
B. Obesity
C. Nutritional deficiencies
D. Hypothyroidism

**Core Concept:**
Gynaecomastia is a condition characterized by the enlargement of the mammary glands in males. It can be caused by various factors, including hormonal, nutritional, and medical conditions.

**Why the Correct Answer is Right:**
The correct answer (D) is "Hypothyroidism" because hypothyroidism primarily affects the thyroid gland and its hormone production, leading to symptoms like fatigue, weight gain, and constipation. Although hypothyroidism can contribute to overall body fat accumulation, it is not directly responsible for causing gynaecomastia.

**Why Each Wrong Option is Incorrect:**
A. Hormonal imbalances: This encompasses various conditions affecting the male endocrine system, including testosterone deficiency and estrogen excess. These hormonal imbalances often lead to gynaecomastia as they disrupt the normal development and functioning of the male reproductive system.

B. Obesity: Obesity can contribute to gynaecomastia by increasing overall body fat accumulation, which can lead to breast tissue enlargement. However, obesity itself is not a cause of gynaecomastia but rather a risk factor.

C. Nutritional deficiencies: Nutritional deficiencies can lead to various health issues, including malnutrition, muscle weakness, and fatigue. While nutritional deficiencies can indirectly contribute to gynaecomastia, they are not direct causes.

**Clinical Pearl:**
Understanding the underlying causes of gynaecomastia is crucial for proper diagnosis and treatment. Knowledge of the correct answer (D) helps differentiate hypothyroidism from the other causes, ensuring accurate management for affected individuals.