symptom onset, not from the time of finding out that you are gene-positive. In regards to having children. If your boyfriend is gene-positive for Huntington's Disease then any children he might have would have a 50% chance of also being gene-positive. However, there are also now a number of reproductive therapies availiable for people with serious hereditary diseases. Click here to find out more about this. I hope this helps. All the best. My sister had HD, and now her son has it, no one else in our family ,mother,daddy, grand parents etc had it what are the odds of this? - Louise (34) Hi Louise, The most likely scenario is that either your mother or father has/had a copy of the mutated Huntingtin gene, despite not showing any symptoms. There are two main ways this could occur. The first is that one of your parents will develop symptoms very late in life (late onset) and therefore their children have a 50% chance of inheriting the Huntington's Disease. The second is a bit more complex and is related to the genetic categories that people can fall in to, as explained below: When people have their genes tested for Huntington's Disease it is to find out if they have a normal or faulty Huntington's gene. They receive a number called a CAG repeat length which tells us how faulty the gene is and can fall within four main categories: 1.Gene-negative: If both copies of a person's HD gene contain 26 or