In this week’s Medical Discovery News by UTMB’s David Niesel and Norbert Herzog: Despite centuries of women being celebrated for siring sons, or scorned for failing to produce an heir, it is actually men who determine a baby’s gender. Women give each of their offspring an X chromosome, but the male can give an X or a Y chromosome to create a female (XX) or male (XY), respectively. But how much of the Y chromosome is required to make a male? It turns out only two genes are needed to create a male mouse, a species that determines gender the same as humans. The column also appears in the Abilene Reporter-News.