Young explorers learn how male and female cells combine when a child is first conceived--and how the genes within each cell determine the characteristics of this new living being. The way in which X and Y genes combine determine whether the child will be a boy or a girl.

This series was written by Prof. Patrick A. Baeuerle, a renowned scientist in the fields of biochemistry and molecular biology, together with Norbert Landa, an experienced author of nonfiction children?s books.