We had that issue too. Just say the mother of the bride is ...... and the father of the bride is. ...... If they have a step parent that has been in there life and is impotant then call out them to . But say it differntyly. The parents of the bride are mother and spouse is MRS ..... and Mr. ....... Then the father of the bride is Mr .... and mrs ..... If ones married and ones not then just leave off that name as there is none. People have this all the time now. But call every parent out if you are calling one step parent as it will cause alot of trouble and the people already know!!!