Is Down syndrome hereditary

I was wondering if Down syndrome hereditary?

[adgal]

Well, not really, no.  Although if you have a ds child, I do believe the odds of having another are slightly higher then it would otherwise be.

DS is actually called Trisonomy 21.  What it means is that the child is born with an extra chromosome.  There is nothing that can be done to prevent it, nor is there anything parents have done to cause it.  It just happens sometimes.  

[Helen72]

Some genetic disorders are hereditory but trisomy 21 is often driven by maternal (or paternal) age.  It can also happen to a young couple with no history of Downs; random chromosomal deviations drive evolution and they do happen although rarely.  These days they have early DS tests available to parents.