Over the last several decades, many biologists have been intrigued with the "immunological paradox" of pregnancy, where maternal and fetal tissues peaceably coexist despite their genetic differences. With the development of new insights on the interactive components of the immune system as well as the generation of powerful new molecular and cellular tools, singular progress has been made in understanding immunological events that culminate in successful pregnancy. This volume contains the proceedings for the first US symposium on the "Immunobiology of Reproduction" held August 26 - 29, 1993 in Boston, Massachusetts. Papers address hemotopoietic cells in reproductive tissues; growth factors/cytokines in the female reproductive tract and placenta; growth factor networks in pregnancy loss and cancer; placental expression of major histocompatibility complex and associated genes; experimental models of MHC gene expression; and immunological aspects of human infertility.