Reproductive Biology

Introduction and Significance

Reproductive BiologyThe study of Reproductive Biology addresses basic aspects of reproduction as well as factors affecting animal and human clinical reproductive health, by examining physiological, cellular, molecular and genetic mechanisms regulating reproductive function. Reproductive biologists within the College of Veterinary Medicine and Biomedical Sciences (CVMBS) investigate gametogenesis, gamete preservation, fertilization, early embryonic development, ovarian and uterine biology, and fetal growth and placental development, and also address the effects of the environment — such as behavior, circadian rhythms, nutrition, and toxins — on reproduction.

Reproductive disorders affect society in diverse ways, from reducing the efficiency of food production to impacting survival of endangered species. A major limitation to improved reproductive efficiency in mammals species is embryonic mortality, which is estimated to be 25% to 60%, depending on the species. In the United States, high rates of unexplained infertility and peri-implantation embryonic loss occur in both humans and domestic animals. The 1995 National Survey of Reproductive BiologyFamily Growth indicated that 15% of women of reproductive age have infertility-associated health-care visits, and the Centers for Disease Control reported 16% of couples in the U.S. experience infertility. Many pregnancy losses in both humans and domestic animals are attributed to asynchrony in signaling between the conceptus (fetus and placenta) and uterus or to endometrial dysfunction, resulting in defective pregnancy recognition, implantation, and/or placentation. In addition, intrauterine growth restriction, a major human health problem in the United States and worldwide, causes significant perinatal complications and may contribute to adult-onset diseases due to involvement of multiple genetic and environmental factors.

From a male perspective, population-based retrospective studies suggest a global decline in semen quality of men and wildlife, influenced by geographical location. The incidence of testicular cancer and congenital reproductive tract abnormalities such as cryptorchidism and hypospadias has increased in men in several study populations. Man-made endocrine-disrupting chemicals, ranging from plastics to pesticides, are thought to play a causal role in these disturbances. Some of these toxins may disrupt sensitive genes in the developing fetal gonad; others affect the post-pubertal male.