**Core Concept**
Somatic stem cells are a type of stem cell that originates from the body's tissues, excluding the germline cells. They have the ability to differentiate into various cell types but have limited self-renewal capacity compared to embryonic stem cells.

**Why the Correct Answer is Right**
The primary disadvantage of somatic stem cells is their limited capacity for self-renewal. This is due to the presence of epigenetic modifications and the expression of specific transcription factors that regulate their differentiation and proliferation. Somatic stem cells typically have a finite number of cell divisions before they undergo senescence or differentiation, which restricts their potential for tissue repair and regeneration.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not applicable as there is no specific disadvantage mentioned.
**Option B:** This option is not a correct disadvantage of somatic stem cells.
**Option C:** This option is not a correct disadvantage of somatic stem cells.

**Clinical Pearl / High-Yield Fact**
The limited self-renewal capacity of somatic stem cells is a key challenge in regenerative medicine, as it restricts their potential for long-term tissue repair and regeneration. Understanding the molecular mechanisms underlying this limitation is crucial for developing strategies to improve the therapeutic potential of somatic stem cells.

**Correct Answer: D**