Can a non biological parent who has voluntarily signed the birth certificate of a child file a motion for DNA years later?

The state where my child support case is established is Illinois. I and this guy were together for three years in a very rocky relationship in which two children were born. He and I both know the girl is his but the boy is not. The children are four and two now and now that he's been put in jail and work release from a child support warrant, he went and filed a motion for DNA on both of the children. I will agree to a DNA test for the boy since we both know the boy isn't his but not the girl. Basically because his family has bonded with her since birth and I don't want to take that away from her. They did nothing for the boy because he isn't his but he did sign the birth certificate. So my question is with him filing a motion in the state of Illinois, although he's signed the birth certificate for both children and has paid no child support, do I have to agree with him for a DNA test on both children?