Step 1: Definition - Amniocentesis is a fetal sex determination and disorder test based on the chromosomal pattern in the amniotic fluid surrounding the developing embryo. Step 2: Purpose - It is primarily used to detect genetic disorders such as Down's syndrome, haemophilia, or sickle-cell anemia in the fetus through chromosomal analysis. Step 3: Legal Aspect - While scientifically useful, it is often misused for female foeticide, which has led to a statutory ban on sex determination in India.