Inheritance laws give illegitimate children, or what the courts sometimes refer to as non-marital children, the same inheritance rights as legitimate children. The laws of inheritance determine who inherits if there is no will, if a will has been contested and denied probate or if the will does not dispose of all of the property. If there is a valid will that disposes of all of the property, it and not the laws of inheritance determine who receives the property. To learn more, look at this page and this page.
The biggest problem that an illegitimate child encounters is the issue of paternity. If everyone agrees that the illegitimate child is the child of the parent, then the child would take a part of the property the same as any other child. If, however, as usually happens, some family members deny that the child is the child of the parent, then the illegitimate child has to prove paternity before he would be entitle to take his share of the property. Each state has time limits within which the child must take action to prove paternity. If the child waits too long, he may not inherit even if he can prove paternity.
Another problem facing an illegitimate child is not knowing who their natural parents are. If a child doesn’t find out who his natural parents are until after their death, he must act quickly or he could loose forever his rights to inherit. The Texas Supreme Court in recent rulings has been tough on children who didn’t start inheritance proceedings in time even in those cases when the child did not know or could not know who his natural parents were. I’ve discussed this issue here. Since the courts are not willing to extend the time for illegitimate children to take action to obtain their inheritance, early action is necessary.