**Core Concept**
The development of permanent teeth in humans is a complex process that involves the replacement of primary teeth, also known as deciduous teeth, with permanent teeth. This process is regulated by a combination of genetic and hormonal factors, and is influenced by the presence of certain enzymes and growth factors.

**Why the Correct Answer is Right**
First permanent teeth typically appear between the ages of 6 to 7 years, when the primary teeth begin to resorb and the permanent teeth start to erupt. This process is initiated by the presence of the hormone calcitonin, which stimulates the development of the permanent teeth. The first permanent teeth to appear are usually the first molars, followed by the second molars, and then the lower central incisors.

**Why Each Wrong Option is Incorrect**
**Option A:** The first permanent teeth do not typically appear at birth, which is the age at which most primary teeth are present.
**Option B:** The first permanent teeth do not usually appear in early childhood, around the age of 2-3 years, as this is the typical age range for the eruption of primary teeth.
**Option C:** The first permanent teeth do not typically appear in late childhood, around the age of 10-12 years, as this is the age range for the eruption of third molars (wisdom teeth).

**Clinical Pearl / High-Yield Fact**
It's worth noting that the timing of the eruption of permanent teeth can vary significantly between individuals, and can be influenced by genetic and environmental factors.

**Correct Answer:** C. 6 years.