I remember this happening to our teacher way back when I was in third grade - she was white, not too young or old. Her husband was a farmer.
I heard a doctor whose son has Downs Syndrome say that our genetic code is so complex that it’s a miracle anyone is born without defects.
My husband says something similar about how improbable it is that the Internet ever works.
I hope the researchers can isolate some contributing factors, thereby helping to reduce the incidence of this condition.