just about everyone carries a gene for at least one genetic disorder — even if it’s never shown up in a family history. if you have a mutation in just one set of genes, you’re what’s known as a “carrier”: you’re carrying the genes for a genetic disorder but have no signs of the disease. our carrier blood test will determine what, if any mutations you and your partner may be carriers for. this will determine if it’s possible for you to pass on any of these diseases to your child.
rarely, a condition (like huntington’s disease) can be caused by a mutation in just one set of dna. but in most cases — including cystic fibrosis and sickle cell disease — it takes a mutation in both sets of dna, one from mom and one from dad, for a child to actually be affected by a genetic disease.