If your children have income that meets the filing threshold, they can file tax returns. They are not going to get child tax credit or any other child-related credits if that is what you are hoping for. Only the parent who can claim a child as a dependent can get the child-related credits --- if the parent is eligible.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**
