Mrs Z is a 47-year-old woman with long-standing infertility who is about to undergo in vitro fertilization (IVF) using donor oocytes from an anonymous donor. She has already undergone an IVF cycle with her own oocytes and an IVF cycle using donor oocytes from a known donor without a successful pregnancy. Mrs Z has been advised by her infertility physician to consider the transfer of a single embryo, but she does not wish to decrease her likelihood of conception, and, after her long and expensive infertility saga, wishes to conceive twins. The science of IVF has evolved significantly in the last several years, increasing the likelihood of successful pregnancy and reducing the need to transfer more than 1 embryo with its inherent risks of multiple pregnancy. The state of the science and why patients may continue to want multiple embryos transferred, including costs and lack of insurance coverage for infertility treatments, are discussed.