Having kids should be one of the first things couples talk about when things start to get serious between them. This topic can singlehandedly end relationships, so to leave that topic out of the relationship can be a big mistake if you want it to work. Couples should talk openly and freely about anything that has to do with having kids – Do you want kids? How many? By what age? How important is it to you? What would happen to our relationship if we discovered that one of us couldn't have kids?…