If your sibling has down syndrome, is there a greater risk that your own baby will have down syndrome?

Depends: Two major types of down syndrome: 1. Non-disjunction type related sometimes to older age of the mother; there is no risk to your baby 2. Translocation type meaning one chromosome is attached to another one: yes you could be normal but carry one chromosome on top of the other and pass that to your baby. This is easy to discover by testing your own chromosomes (a blood test).

I wouldn't worry: By definition you don't have it, which is important. Having it in a close relative raises your risk at most by 1%, which you must add to whatever your risk is for age.At 38, that is about 1%,so if you are looking at 2%, the choice is yours as to whether to freak out or not.A meeting with a clinical geneticist could explore this and any other hidden issue on both sides of the family. More info=btr