Natural children are the biological children of their parents. This article discusses the inheritance rights of those children.
In Texas, in general, children inherit the estate of their parents if there is no valid will. The spouse of the parent will also inherit a portion of the estate. How much the spouse inherits depends on whether the spouse is also the parent of the children (more) or the step parent of the children (less.) Read here for a discussion of the kinds of property involved and what the spouse and children receive when there is no will.