Which one of the following conditions of the zygotic cell would lead to the birth of a normal human female child?

Options

A. two X chromosomes
B. Only one Y chromosome
C. Only one X chromosome
D. One X and one Y chromosome

Answer

To determine which condition of the zygotic cell would lead to the birth of a normal human female child, we need to analyze the chromosomal makeup of human beings, particularly focusing on the sex chromosomes.

### Step-by-Step Solution:

1. **Understand Human Chromosomes**:
- Humans have a total of 46 chromosomes, which consist of 22 pairs of autosomes and 1 pair of sex chromosomes.

2. **Identify Sex Chromosomes**:
- The sex chromosomes are designated as X and Y. Females typically have two X chromosomes (XX), while males have one X and one Y chromosome (XY).

3. **Determine Female Zygotic Condition**:
- For a zygote to develop into a normal female child, it must have two X chromosomes (XX).

4. **Evaluate the Options**:
- **Option A: Two X chromosomes (XX)** - This is the condition that would lead to the birth of a normal female child.
- **Option B: Only one Y chromosome (Y)** - This is incorrect because a Y chromosome alone cannot lead to the development of a female.
- **Option C: Only one X chromosome (X)** - This is incorrect as a single X chromosome does not provide the necessary genetic information for a female.
- **Option D: Only X and only Y chromosomes (XY)** - This combination indicates a male child, not a female.

5. **Conclusion**:
- The correct answer is **Option A: Two X chromosomes (XX)**, as this is the only condition that leads to the birth of a normal human female child.