Redefining marriage brings about social change. A small part of this change is positive, but it also brings about a lot of negative social outcomes too. In this lecture, we look at how, in a marriage redefined culture, it becomes ever harder for heterosexuals to understand that marriage is primarily about giving their biological children the best possible start in life. Thus more heterosexuals won't marry in order to protect their children and more will divorce. This being so then more children will suffer and future society goes even more into decay.