Dr. Davis performs research in the area of hormonal control of reproduction. Developing catfish fry fed estrogenic or androgenic hormones will become functional females. Thus males, containing the XY genotype, are sex reversed to become XY females. Eventual mating of XY females with normal XY males produces XX female offspring, XY male offspring, and YY male offspring. Sex reversal of these offspring can also lead to production of YY females. These males could then be stocked in ponds with normal XX females to produce all male offspring for food production. Research is ongoing to develop molecular tests to efficiently identify which male catfish carry the YY genotype, produce YY males in large numbers, and compare in large scale studies the performance of all male populations with mixed sex populations currently used in production. Correlated experiments involve the use of shortened cycles of annual warm and cold water temperatures to accelerate the time to sexual maturation.