Step 1: Understand the question.
We must find what kind of disorders amniocentesis can detect in an unborn baby.
Step 2: Recall what amniocentesis is.
Amniocentesis is a test done during pregnancy. A small sample of the fluid around the baby, the amniotic fluid, is drawn out with a fine needle.
Step 3: See what the fluid contains.
This fluid carries cells shed by the baby. These cells hold the baby's chromosomes and genes.
Step 4: Know what is examined.
Doctors study these cells to check the number and shape of chromosomes and to look for gene faults.
Step 5: Decide the type of disorder.
Because the test reads chromosomes and genes, it mainly finds genetic disorders, such as Down syndrome. It is not made to check the heart, kidney, or brain directly.
Step 6: State the answer.
So amniocentesis helps detect genetic disorders.
\[ \boxed{\text{Genetic disorders}} \]