Genes and Inheritance
The Mixing of Genes Between You and Your Partner Determine the Physical and Mental Characteristics of your Child
A baby attains half of its genes from its father and half from its mother. Each sperm and egg have 23 chromosomes, which combine to form the 46 chromosomes in the resulting child. Every egg is comprised of X chromosomes, since the general chromosomal makeup of a woman is XX, or two X chromosomes. Similarly, and conversely, each sperm can be one of two chromosomes. Sperm can be comprised of either an X chromosome or a Y chromosome, since the general chromosomal makeup of a man is XY. Gender is determined at the moment of conception, since an X chromosome egg is either penetrated by a X chromosome sperm or a Y chromosome sperm.