**Core Concept**
The Sertoli cells play a crucial role in the maintenance of spermatogenesis. They provide structural support to the developing sperm cells, regulate the blood-testis barrier, and produce androgen-binding protein and inhibin. Selective destruction of Sertoli cells would disrupt these functions, affecting spermatogenesis.

**Why the Correct Answer is Right**
The correct answer is related to the disruption of spermatogenesis due to the destruction of Sertoli cells. Sertoli cells produce inhibin, which is a protein that regulates FSH (follicle-stimulating hormone) production. With the destruction of Sertoli cells, inhibin production decreases, leading to an increase in FSH levels. This increase in FSH can stimulate the remaining Sertoli cells, but it cannot compensate for the loss of their function, resulting in a decrease in spermatogenesis.

**Why Each Wrong Option is Incorrect**
* **Option A:** Increased testicular size is not a direct consequence of selective destruction of Sertoli cells. It might be seen in conditions like Klinefelter syndrome or testicular cancer.
* **Option B:** Decreased testosterone levels are not a direct consequence of selective destruction of Sertoli cells. Testosterone production is primarily regulated by Leydig cells.
* **Option C:** Increased estrogen levels are not a direct consequence of selective destruction of Sertoli cells. Estrogen production is primarily regulated by Sertoli cells, but its increase is not a direct consequence of their destruction.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that Sertoli cells are responsible for the regulation of spermatogenesis, and their destruction can lead to a decrease in sperm count and fertility. This is an important consideration in the evaluation of patients with testicular disorders.

**Correct Answer: D. Decreased spermatogenesis**