Congenital chromosomal and metabolic defects in the foetus can be determined by amniocentesis.

Answer

### Step-by-Step Solution:

1. **Understanding Amniocentesis**:
- Amniocentesis is a medical procedure used during pregnancy to obtain a sample of amniotic fluid, which contains fetal cells and various substances.
- This procedure is typically performed between the 15th and 20th weeks of pregnancy.

2. **Purpose of Amniocentesis**:
- The primary purpose of amniocentesis is to diagnose congenital chromosomal abnormalities and metabolic defects in the fetus.
- It allows for the analysis of the fetal genetic material and helps in identifying conditions such as Down syndrome, cystic fibrosis, and other genetic disorders.

3. **Procedure**:
- A thin needle is inserted through the abdominal wall into the uterus, guided by ultrasound, to collect a small amount of amniotic fluid.
- The collected fluid is then sent to a laboratory for analysis.

4. **Analysis of Amniotic Fluid**:
- The fetal cells in the amniotic fluid can be cultured and analyzed for chromosomal patterns.
- Genetic testing can reveal whether the fetus has any chromosomal abnormalities or metabolic disorders.

5. **Ethical Concerns**:
- While amniocentesis is a valuable diagnostic tool, it has been misused in some cases to determine the sex of the fetus.
- This misuse can lead to sex-selective abortions, which is illegal and raises ethical concerns regarding gender discrimination and its impact on the male-female ratio in society.

6. **Conclusion**:
- The statement that congenital chromosomal and metabolic defects in the fetus can be determined by amniocentesis is correct.
- It is important to use this procedure responsibly and ethically to avoid misuse.