Hoping and Praying for a baby

So my fiancé and I have been together for 2 years. I have 3 kids from a previous marriage and he has 2 from a previous marriage. We want another baby together, but our families are completely against it. They feel we have enough kids. Him and I live together, have great careers, and take great care of our children. There really isn't any reason for them not to support our decision, other than they feel like we have enough children. I hope and pray that we can have another baby to family and that our families will accept him or her once we do.