The phrase "birth child" refers to a child that is born to and biologically related to their parents, as opposed to a child that is adopted or brought into a family through other means. Full definition
There are a few opportunities for assistance in the form of scholarships specifically for multiple birth children. (verywellfamily.com)
Think of it this way: marriages break up sometimes, but the birth parent - birth child relationship is never going to dissolve. (freeprintablebehaviorcharts.com)
I can not see how I could love my own birth child any more than I love him. (americaadopts.com)