Twin 13-year-old brothers were arrested and charged with rape, sex abuse, burglary, robbery and assault involving a 40-year-old woman.  They will be tried as juveniles.  The attack took place in the woman's Bronx apartment after she returned home with groceries.  The twins who are 5 feet tall and weigh 108 pounds allegedly stole $375 in cash and fled.  While on of the boys beat and raped her his twin held down the woman's 2 year old son, covering his mouth to keep him from screaming for help.  The victim was treated for bruises and released from the hospital.  Sources said the boys were charged two years ago in another brutal attack, the reported rape of a 5 year old cousin.  The outcome of that case was not immediately clear.