Original articles, 42-45 | DOI: 10.53260/GREM.212017 Effect on vitrification on same number of oocytes from different oocytes cohorts in donors’ cycles Mario Alberto Garza-Garza, Lilyana Carolina de la O Tamez, José Iram Obeso Montoya, S. Alberto Dávila Garza, Genaro García Villafaña