Since the first children were born using in vitro fertilization (IVF) in 1978 and IVF with intracytoplasmic sperm injection (ICSI) in 1992, several million children have been conceived using these techniques. In some countries, ICSI-conceived babies account for 4 percent of newborns. IVF and ICSI facilitate the transmission of genetic material and associated epigenetic marks of these genes to offspring that would not have otherwise occurred. They also circumvent the normal maturation steps of the genetic material, expose that material to artificial laboratory conditions, and bypass selective barriers involved in normal fertilization. Nevertheless, these methods appear to be effective methods for treatment of infertility and relatively safe despite a small increase in congenital abnormalities of the offspring. The symposium will review the biological considerations in the development of the IVF and ICSI technology and provide an update on the further developmental outcomes of these children. The concerns associated with the transmission of genetic defects in the parents, which would have otherwise been selected against by the failure of reproduction, will be addressed. In addition, novel genetic abnormalities arising from fertilization by developmentally abnormal gametes, including de novo chromosomal abnormalities, trinucleotide expansion diseases, and disorders of abnormalities in genomic imprinting will be described and evaluated.