This study will compare two alternative embryo culture systems. Embryos from each patient will be randomly assigned to one of two systems. One group will be cultured conventionally in oil-covered droplets in dishes. The other group will be assigned to an enclosed system.

Qualifying and consenting IVF patients will have approximately half of their developing embryos cultured in droplets covered with oil. The other approximate half of their embryos will be cultured in small enclosed containers. Embryo assignments will be at random. Regardless of culture system, all embryos will be cultured from the bipronuclear stage to the blastocyst stage in the same (Global) media, without the usual refreshing of media on day 3.

Inclusion Criteria:

• Female age 18 to 40, seeking IVF treatment
• Ability to understand English (to obtain informed consent)
• Use of an oocyte donor, sperm donor, gestational carrier, and/or genetic testing (with blastocyst biopsy only) are allowed.

Exclusion Criteria:

• Diminished ovarian reserve as evidenced by either elevated cycle day 3 follicle stimulating hormone (FSH) level (≥10 IU/L) or low antral follicle count (<8 antral follicles)
• Fewer than five (5) bipronuclear oocytes
• Day 3 embryo biopsy for any reason
• No minors may enroll