The purpose of this study is to determine if cryopreservation at the blastocyst stage followed by embryo thaw and transfer is as effective as cryopreservation of bipronuclear oocytes followed by post-thaw extended culture (PTEC), and blastocyst transfer. Effectiveness will be measured by the rate of ongoing pregnancy at 10 weeks gestation.

Subjects will be randomized to one of two study groups during their cycles of in vitro fertilization (IVF). In one group, the subjects will have all of their embryos cryopreserved at the blastocyst stage, followed by thaw and transfer in a subsequent cycle. In the other group, subjects will have all of their embryos cryopreserved at the bipronuclear oocyte stage, followed by thaw, extended culture, and transfer in a subsequent cycle.

Inclusion Criteria:

1. Female patient seeking autologous in vitro fertilization (IVF) treatment.
2. Cycle day 3 serum concentration of follicle stimulating hormone (FSH) less than 10.0 IU/l.
3. Baseline total antral follicle count observed on ultrasound with at least eight antral follicles.
4. 18 to 40 years of age.
5. Ability to read and understand English.

Exclusion Criteria:

1. Embryo biopsy (a.k.a. pre-implantation genetic diagnosis (PGD)).
2. Any condition that, in the opinion of the physician or principal investigator, would place the patient at undue risk under this protocol or would otherwise make the protocol inappropriate for that subject.
3. No minors will be enrolled in this study.