Spencer’s laboratory seeks to define critical physiological and genetic pathways that regulate uterine development, function, and regeneration in order to improve reproduction and health of women and animals. His earlier work established that the glands of the uterus are essential for embryo survival and growth using the ovine uterine gland knockout model. Subsequent research revealed fundamental aspects of postnatal uterine development and uterine receptivity as well as illuminated the evolutionary biology and functional role of endogenous retroviruses in placental development. Current research foci in his lab include: cellular and molecular mechanisms governing development of the uterus; maternal and paternal regulation of pregnancy establishment in cattle; placental development in domestic animals; development of animal models to study uterine function; and biological roles of uterine glands and their products in uterine receptivity, stromal cell decidualization, and placental development.