My fiancé has the same concerns. She was stuttering since she was 5. She said she stuttered less in her 20s but it's coming more frequent. In addition to that, she also suffers from bad asthma - in both cases her stuttering and asthma is genetic and she is worried to pass it on if we have kids. The thing is she's amazing with kids and loves them and I know she would make a great, supportive mother and she does want kids but on the other hand she fears on passing her "hiccups" onto them. But I tell her that if we have kids who stutter - they will be lucky to have a parent who can understand what they are going through and the child will have a best supporter of their lives! Our wedding is this September and we'll still wait before having kids but I do believe someone who stutters shouldn't fear on passing it on their kids.