If two people carry the same genetic mutation and have a child together, that child is at risk of a genetic disorder. Some of the more common mutations that result in disease are cystic fibrosis, spinal muscular atrophy, and sickle cell trait. However, current tests allow us to check over 100 mutations for each patient. Most children born with a genetic condition have no family history of that disease, since carriers are typically unaware they have a genetic mutation. These mutations are typically recessive, or ‘silent,’ in carriers with one mutated copy and one normal copy of the gene. 

If both parents are carriers, the child has a 25% chance of inheriting the parents’ abnormal genes and having the disorder. There is a 50% chance the child will be a carrier of the disorder — like the carrier parent. There is a 25% chance the child will only inherit the normal genes. If only one parent is a carrier, the child has a 50% chance of becoming a carrier and a 0% chance of having the disorder.