Amniocentesis in a technique by which hereditary disorders due to defects in genes can be detected. In this technique

  1. a small sample of amniotic fluid which surrounds the foetus is syringed out.
  2. This fluid has cells which break off from the skin of the foetus.
  3. Foetal cells are picked up and cultured.
  4. Chromosomes in the dividing cells are analysed for genetic defects.

If incurable genetic defects are detected, pregnancy can be terminated.