Complex sentence: If one of these cells contributes to the genetic makeup of a child, the child will have an extra X chromosome in each of her cells.blah blah blah cases, trisomy X occurs during cell division in early embryonic development.
Split into simpler sentences: If one of these cells contributes to the genetic makeup of a child, the child will have an extra X chromosome in each of her cells. In some cases, trisomy X occurs during cell division in early embryonic development.