Mich. Comp. Laws § 552.45
Every bill of complaint filed shall set forth the names and ages of all children of the marriage, and if there are children under 17 years of age a copy of the summons issued in the cause shall be served upon the prosecuting attorney of the county where suit is commenced, or upon the friend of the court in those counties having a population of 500,000 or more that have a friend of the court. The prosecuting attorney or friend of the court so served may enter his or her appearance in the cause, and if, in his or her judgment, the interest of the children or the public good so requires, he or she shall introduce evidence and appear at the hearing and oppose the granting of a decree of divorce. In a case in which there are no children the issue of such marriage under the age of 17 years, if it appears to the court that the public good requires, an order may be entered requiring the prosecuting attorney or friend of the court in counties having a population of 500,000 or more to appear and oppose the granting of a decree of divorce. Nothing in this act prevents prosecuting attorneys or their partners from acting as solicitors or counsel for either party to the suit. If a prosecuting attorney or friend of the court is in any way interested as solicitor or counsel for either of the parties the court shall appoint some reputable attorney to perform the services of prosecuting attorney, as provided in this act, who shall receive the compensation provided for such service.
MCL 552.45