**Core Concept**
The question is testing the understanding of Fragile X syndrome, a genetic disorder causing intellectual disability. Fragile X syndrome is an X-linked dominant disorder caused by an expansion of CGG repeats in the FMR1 gene, leading to the silencing of the gene and subsequent deficiency of the FMRP protein. This protein is crucial for normal brain development and function.

**Why the Correct Answer is Right**
The correct answer is related to Fragile X syndrome. The FMR1 gene is located on the X chromosome, and males, who have only one X chromosome, are more likely to express the disorder. The expansion of CGG repeats in the FMR1 gene leads to the silencing of the gene, resulting in the deficiency of FMRP protein. This deficiency disrupts normal brain development and function, leading to intellectual disability. The severity of the disorder can increase over generations due to the expansion of CGG repeats, making it more likely for males to express the disorder.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is likely incorrect because it does not relate to the specific genetic disorder causing increasing severity of mental retardation in male members over generations.
* **Option B:** This option may be incorrect because it does not specifically relate to the FMR1 gene or the expansion of CGG repeats, which are key factors in Fragile X syndrome.
* **Option D:** This option may be incorrect because it does not provide a clear explanation for the increasing severity of mental retardation in male members over generations.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that Fragile X syndrome is the most common cause of inherited intellectual disability, and males are more likely to express the disorder due to the absence of a second X chromosome.

**Correct Answer:** C.