Successful implantation and early development need a union of healthy genes and an optimal uterine environment. The 48th RCOG Study Group, an international multidisciplinary expert forum, considered factors involved in preparation for implantation within the uterus; how to determine a good egg and good sperm; lessons from animal models; transgenic and genomic technologies; sporadic and recurrent early pregnancy loss; single-embryo transfer; and the developmental consequences of assisted reproduction technologies. This book presents the findings of the Study Group, with sections covering: • preparation for implantation - the uterine environment • the embryo • lessons from animal models (transgenics) and novel technologies • clinical sequelae.