what is the normal percentage of having a downs baby is 1 in 285 high?

Answer 1

Not sure about that, but here is some information-

The most common genetic disorder is the one that causes Down syndrome, once known as mongolism. Children with this syndrome have an extra chromosome in pair 21, and thus have 47 instead of 46 chromosomes. Information from the extra chromosome influence development, resulting in superficial external anomalies (slanted eyes, deformed eyes, and abnormal hands) and many internal ones, affecting intellectual ability among other things. The risk of having a child with Down syndrome is greater in older women, but it occurs even with young couples. Because the majority of all babies are born to younger parents, most parents of children with Down syndrome are young enough tot be in a ge group that, in most countries, does not routinely receive this diagnostic testing. In any case, not all couples who receive this diagnostic decide to terminate the pregnancy. Parents and siblings of children with Down syndrome have often testified about how these children enrich the lives of the other family members. Moreover, the degree of mental disability associated with the syndrome varies widely.

1 out of 700 children are born with Down syndrome, and its on the rise.

Answer 2

Are you asking if that's high? Because that's a 0.35% chance of having a baby with Down Syndrome, which is generally considered very low.