On day 3 or day 5 of embryo development, all patients will undergo a two (2) embryo transfer. The embryos selected for transfer will be the 2 morphologically best of the embryo cohort. Once selected for transfer, the embryos will be randomized so that one will be biopsied and the other will be transferred without undergoing biopsy. The embryo randomized to biopsy will have a single cell biopsied.