**Core Concept**
Congenital cataracts refer to the opacification of the lens in the eye that occurs at birth. This is a rare condition that affects the visual development of the infant. The exact cause of congenital cataracts is often unknown, but it can be associated with genetic mutations, intrauterine infections, or exposure to certain medications during pregnancy.

**Why the Correct Answer is Right**
The correct answer is related to the association of congenital cataracts with galactosemia, a genetic disorder that affects the body's ability to metabolize the sugar galactose. Infants with galactosemia are unable to break down galactose, leading to its accumulation in the body. When galactose is converted to galactitol, it can cause lens opacification, resulting in congenital cataracts. This is because galactitol can disrupt the normal metabolism of the lens, leading to its opacity.

**Why Each Wrong Option is Incorrect**
* **Option A:** Congenital cataracts can be caused by other factors, such as intrauterine infections or exposure to certain medications during pregnancy, but galactosemia is a specific and well-established association.
* **Option B:** While diabetes can cause cataracts in adults, it is not a known cause of congenital cataracts in newborns.
* **Option C:** Congenital glaucoma is a separate condition that affects the intraocular pressure and can cause vision problems in infants, but it is not directly related to cataract formation.

**Clinical Pearl / High-Yield Fact**
Galactosemia is a treatable condition, and early diagnosis and management can prevent the development of congenital cataracts. This highlights the importance of monitoring infants for signs of galactosemia, such as poor feeding, vomiting, and lethargy, and ensuring that they receive a galactose-free diet if diagnosed.

**Correct Answer: D. Galactosemia.**