This chapter uses data from the Yomut to test the Trivers-Willard hypothesis. The Yomut occupy a high position in a hypergynous hierarchy of descent and ethnic groups and appear to raise more sons than daughters as a consequence. The Yomut Turkmen are one of several large Turkmen descent groups occupying a contiguous area in Central Asian Turkestan. The Yomut themselves are adept at moving from knowledge of a person's animal year to his or her age, and most Yomut can state their age when asked. The Yomut were effectively at the top of a hypergynous system of ethnic stratification. The reproductive lifespans of Yomut men and women are very different. The average age at reproduction for Yomut women is 30.1 and the average age at reproduction for men is 39.6. Yomut men enjoy a higher reproductive success on average than Yomut women, and Yomut parents take advantage of this fact by raising more sons than daughters.