Every child is eligible for government benefits related to the child's biological or legal parents, including Social Security survivorship benefits, government pension benefits, and the like. The key is to ensure birth certificate and paternity issues are resolved as soon as, or shortly after, the child is born.
Once that's done, you can be assured that, if tragedy strikes you or your partner, your child will be covered. If you neglect to establish yourself as a legal parent -- for example, by failing to put your name on the birth certificate -- and your child seeks government benefits after your death, the agency may deny his or her request because there isn't any proof that you were the parent.