**Core Concept**
The skull of a human being develops and changes throughout life due to various factors such as genetics, hormones, and growth patterns. Before puberty, the skull's development is influenced by sex hormones, leading to distinct differences between males and females.

**Why the Correct Answer is Right**
In males, the presence of testosterone before puberty causes the cranial sutures to close earlier, resulting in a more compact skull with a smaller cranial capacity. In females, the lower levels of androgens allow the cranial sutures to remain open for a longer period, leading to a larger cranial capacity and a generally more open skull. This difference is due to the effects of sex hormones on the growth and development of the skull bones.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not accurately describe the differences in skull development between males and females before puberty.
* **Option B:** This option is incorrect as it is a generalization and does not account for the specific effects of sex hormones on the skull's development.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the differences in skull development between males and females are primarily due to the effects of sex hormones, which become more pronounced during puberty. This knowledge is crucial in forensic anthropology and craniometry.

**Correct Answer: D.** The difference in skull development between males and females before puberty is primarily due to the effects of sex hormones, with males having a more compact skull and females having a larger cranial capacity.