**Core Concept**
Benign prostatic hypertrophy (BPH) is a condition characterized by the enlargement of the prostate gland, leading to urinary retention and other symptoms. The growth of the prostate gland in BPH is primarily driven by an increase in the number of stromal and epithelial cells.

**Why the Correct Answer is Right**
The growth of the prostate gland in BPH is primarily due to an increase in dihydrotestosterone (DHT) levels, which stimulates the growth of stromal and epithelial cells. DHT is an active form of testosterone, produced by the enzyme 5-alpha-reductase. The increased levels of DHT lead to an increase in the expression of growth factors, such as fibroblast growth factor (FGF) and epidermal growth factor (EGF), which promote cell proliferation and hypertrophy.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the underlying mechanism of BPH. While inflammation may play a role in the development of BPH, it is not the primary cause of prostatic growth.

**Option B:** This option is incorrect because it is not supported by scientific evidence. The growth of the prostate gland in BPH is not primarily due to an increase in estrogen levels.

**Option C:** This option is incorrect because it is not a well-established mechanism of BPH. While genetic factors may contribute to the development of BPH, they are not the primary cause of prostatic growth.

**Clinical Pearl / High-Yield Fact**
A key clinical feature of BPH is the presence of an enlarged prostate gland, which can be confirmed by digital rectal examination (DRE). The DRE is a simple, non-invasive test that can help diagnose BPH and guide further management.

**Correct Answer: A. Increased DHT levels.**