Infertile women who are candidates for ART will be prospectively screened for enrollment at 24 clinical trial sites in the United States and Argentina. Enrolled subjects will start treatment using oral contraceptives (OCP) and will then receive a Gonadotropin releasing hormone (GnRH)-agonist (leuprolide acetate) for pituitary desensitization. Once down-regulation is achieved, the subjects will be randomized in a 1:1:1:1 ratio to begin ovarian stimulation with one of 3 doses of AS900672-Enriched or with follitropin alfa (Gonal-f®) daily injections. Subjects will be recruited to the four study arms in parallel. Beginning on S1, the subjects will receive either a single injection of AS900672-Enriched or start daily injections of follitropin alfa. The subjects' response to treatment will be monitored by ovarian ultrasound and E2 levels. On S6, subjects randomized to AS900672-Enriched may begin receiving supplemental follitropin alfa 150 IU, according to the each subject's ovarian response, and subjects randomized to follitropin alfa 150 IU daily injections will continue treatment at the same dose. Recombinant human chorionic gonadotropin (r-hCG, Ovidrel®) will be administered to subjects meeting response criteria and who are not at risk for ovarian hyperstimulation syndrome (OHSS). Oocyte retrieval will occur within 34-38 hours after r-hCG administration and subjects will begin luteal phase support using vaginal progesterone (Crinone® 8 percent or Prochieve® 8 percent) the following day. Fertilization will be done by conventional IVF or ICSI. Embryo transfer will occur in accordance with the specific requirements of each subject and the clinical trial site's standard practice, with the exception that a maximum of two embryos at the cleavage or blastocyst stage may be transferred. Subjects who undergo embryo transfer will be assessed for pregnancy and a follow-up visit will be performed 15-20 days post r-hCG administration. Subjects with a positive pregnancy test will undergo a confirmatory ultrasound evaluation at Day 35 - 42 post r-hCG. Additionally, all subjects recruited at certain trial centers will participate in a pharmacokinetic (PK) sub-study.