Amniocentesis has helped

Answer

### Step-by-Step Solution:

1. **Understanding Amniocentesis**:
- Amniocentesis is a medical procedure used during pregnancy to obtain amniotic fluid, which surrounds the fetus in the uterus. This fluid contains cells from the fetus that can be analyzed for genetic information.

2. **Purpose of Amniocentesis**:
- The primary purpose of amniocentesis is to check for chromosomal abnormalities in the developing fetus. This can include conditions such as Down syndrome or other genetic disorders.

3. **Gender Determination**:
- Amniocentesis can also be used to determine the sex of the fetus. This is particularly relevant in regions where there is a preference for male children, leading to a skewed male-to-female ratio.

4. **Impact on Childless Couples**:
- The question mentions "childless couples." Amniocentesis is not applicable to childless couples as it is performed during pregnancy. Therefore, it does not help them directly.

5. **Conclusion**:
- Among the given options, the correct answer is that amniocentesis has helped in the establishment of the biological superiority of females in regions with a disturbed male-to-female ratio. This is because it can reveal the gender of the fetus, which may influence societal preferences.

### Final Answer:
Amniocentesis has helped in the establishment of the biological superiority of females in regions with a disturbed male-to-female ratio.

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