Children traveling internationally require the same documentation as adults, that means that even the youngest babies need to get a passport or other accepted ID
International Child Abduction laws mean that you'll need a little more advance preparation and documentation if you are a parent traveling without your spouse, a grandparent, or if your last name is different from your child's last name.
Note: Unfortunately I am unable to give advice about specific destinations or situations. Check with your country’s state department, and the embassy of each country you will be visiting regarding the latest regulations and requirements. Try to get written instructions that you can carry with you in case any questions arise at immigration. For US Citizens, the state department website is travel.state.gov