Naturally, you should indicate all the children you have on Form N-400. This information is provided in Part 11 entitled as “Information About Your Children”. Fill it out as it is mentioned below.
Item Number 1. You should provide a total number of children. All children nevertheless if they are alive, have been missed or died; born abroad or in the USA; 18 years senior or junior; married or not; residing next to you or far away; are stepchildren or legally adopted ones; born in the not official marriage should be counted.
Item Number 2. Give details about every child listed in the previous item. You should include child’s current legal name; A-number if there is any; date and country of birth (the last one should be indicated in the way it sounded at the time when your child was born); relationship to you (e.g. biological, step, legally adopted) and current address http://faq-n-400.com/