Whether or not they should is a matter for GD. My question is a purely biological one.
I know I’ve never heard of one having a child. I guess if they did there would be a 50/50 chance of their child getting the extra chromosome. So there’d be a 50/50 chance of their offspring having Down Syndrome, right?
As I said I never heard of one having a baby. But that doesn’t mean it hasn’t happened.
The short answer is yes, people with Down Syndrome can and do have babies, though as the National Down Syndrome Society points out, about 50% of women with Down Syndrome are fertile, and men with the syndrome "have a significantly lower overall fertility rate than that of other men of comparable ages.+ Between a third and a half of children born to someone with Down Syndrome will have trisomy 21 or other developmental issues.