A couple has six daughters. What is the possibility of their having a girl next time ?

Options

A. `10 %`
B. `50 %`
C. `90 %`
D. `100 %`

Explanation

To determine the possibility of a couple having a girl after already having six daughters, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Genetic Basis**:
- In humans, sex determination is based on the combination of sex chromosomes contributed by the parents. Females have two X chromosomes (XX), while males have one X and one Y chromosome (XY).

2. **Identify the Parent Contributions**:
- The mother (female) will always contribute an X chromosome. The father (male) can contribute either an X or a Y chromosome.

3. **Determine Possible Outcomes**:
- If the father contributes an X chromosome, the combination will be XX, resulting in a girl.
- If the father contributes a Y chromosome, the combination will be XY, resulting in a boy.

4. **Calculate the Probability**:
- Since the father has an equal chance of contributing either an X or a Y chromosome, the probability of having a girl (XX) is 50%, and the probability of having a boy (XY) is also 50%.

5. **Conclusion**:
- Therefore, regardless of the previous births, the probability of the couple having a girl next time remains 50%.

### Final Answer:
The possibility of the couple having a girl next time is **50%**.

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