You MUST have a Social Security Number (SSN) for all dependents that are listed on your tax return. Even a baby born at 11:00 on New Year's Eve. To obtain a SSN, get form SS-5. You can go to your Social Security office or call 800-TAX-FORM. If you don't have a SSN for a dependent on your tax return, you lose the $2700 personal exeption reduction. There are no exceptions. Hospitals now help new parents before they take home the new bundle of joy by giving them the forms to fill out. If you know someone starting their family; help them out by telling them to do this at the hopital. Sleepless nights with babies won't make SSN's something to deal with later.