Does a child have to testify against parent if they were supboened to testify?

There are no child/parent privileges that can prevent a child from testifying against a parent in a criminal proceeding, it happens everyday. If your child was subpoenaed and order to come to court to testify against you, then the prosecutor or attorney who issued the subpoena is within their legal rights because your child will be treated as a witness in a criminal case. There is a spousal privilege that prevents a spouse from testifying against another spouse if that spouse (you in this matter) wishes to invoke that privilege.