How can two physically healthy parents produce a child with Down syndrome and a second child with Klinefelter syndrome?

This can happen because of genes and other difficulties that their family members have had.

The virus is considered to be are living item since they have hereditary material dnas or rnas. they can imitate and change. they respond to boosts, for example, radiation, chemicals, and warmth. they have antigenic properties. they are proficient to duplicate with a same hereditary constituent.