The current debates about gender, the meaning of marriage and human sexuality are of interest to people inside and outside the Christian churches. A massive exercise in social engineering is underway around the world and it is often difficult to discern how Christians might contribute to the debate in a way that will not simply be dismissed as traditionalist bigotry. The Sydney Diocesan Doctrine Commission has spent two years reflecting upon the issues and has produced this little book as a resource for Christians who wish to understand what is happening and how they might respond, as well as an explanation to others of why Christians have found the debate and the way it has been conducted in the public arena deeply disturbing.