Preimplantation Genetic Screening (PGS) is used for the selection of chromosomally normal embryos before the transfer in IVF treatments in many cases. There is great debate in the scientific community as to whether this is an efficient practice in patients of different prognosis.

This prospective and randomized study seeks to study the results of chromosomal diagnosis using the new Comparative Genomic hybridization (CGH) arrays technique by practicing Preimplantation Genetic Screening (PGS) in day three biopsy on one arm of the study and not on the other arm in order to compare the results. The investigators will study the ongoing pregnancy rate of each oocyte retrieval and the ongoing implantation rate with Day 5 embryos (blastocysts) in IVF/ intracytoplasmic sperm injection (ICSI) treatments of embryos from two different groups of patients: Advanced Age Female Patients (38 - 41 years of age) and Male severe factor (≥2 million spermatozoids/ml.).

The randomized controlled trial results of advanced maternal age was completed and published (Rubio et al., Fertility&Sterility 2017).

The randomized controlled trial results of the male factor indication was terminated with anticipation due to the change of the technology that prevented recruitment of patients using the old technology (that one used in the study).

Inclusion Criteria: ADVANCED AGE and SEVERE MALE FACTOR:

• Women's Age: 38- 41 years old (both included)
• Men's Age: 18-60 years old (both included)
• Ovulation triggered with human chorionic gonadotrophin (hCG) (Ovitrelle, Merck-Serono, Madrid)
• Number of Oocytes metaphase II (MII): ≥ 5 (fresh, not vitrified)
• Quality of semen: ≥ 5 millions spermatozoids/ml

Exclusion Criteria: ADVANCED AGE and SEVERE MALE FACTOR:

• Number of Oocytes metaphase II (MII): <5 oocytes
• Number of Oocytes obtained: >20
• Estradiol on the day of human chorionic gonadotrophin (hCG) >3000 pgr/ml administration.
• Progesterone on the day of hCG >1,5 pmol/l administration
• ≥ 2 previous miscarriages:biochemical,clinical,ectopic or a combination)
• Any un corrected alteration in a previous study.
• Other indications of (Preimplantation Genetic Diagnosis.Screening) PGD-S, such as monogenic illnesses, translocations, repeated implantation failure, repeated miscarriages, etc.