The physiological regulation of the sexual cycle and also pathological changes in the ovaries and uterus of various animal species are central to our research in the area of reproduction. Studies of the comparative morphology of the ovaries as well as the varied development of the gonads in different species facilitate a better understanding of pathological changes and infertility. One of the Institute’s speciality areas is the three-dimensional reconstruction of equine embryos in different stages of development out of semi-thin sections and their associated ultrastructural representation via electron microscope. In addition to topics relevant to developmental biology, our research focuses on pathological changes in the endometrium of dogs and horses. In addition to histological, immunohistochemical and molecular biological analytical procedures, a cell culture model of the canine endometrium established at our Institute is used for experimental approaches. The “reconstruction” of the endometrium in the laboratory allows specific investigations of the physiology and pathology of the endometrium without having to resort to animal experiments.