If you have a gun at home and a robber tries to rob you can you shoot them?

Of course you can, but you may be prosecuted for it! Laws vary from state to state, and the CASTLE DOCTRINE has been enacted in many states which give the home owner protection from suits if he were to use lethal force. Some states require retreat to the furthest part of the house before use of force is allowed. This is a difficult question and you should contact your State Attorney General for guidance.