A method for selecting an oocyte that when fertilized produces a viable embryo with a high implantation rate leading to pregnancy comprising a step of: a) measuring the expression level of 45 genes in a cumulus cell surrounding said oocyte, wherein said 45 genes are wingless-type MMTV integration site family, member 6, leucine-rich repeats and calponin homology domain containing (LRCH4), paired box 8, calcium binding protein 4 (CABP4), phosphodiesterase 5A, cGMP-specific (PDE5A), BCL2-like 11 (BCL2L11), phosphoenolpyruvate carboxykinase 1, transcription factor 20, SLAM family member 6 (SLAMF6), erythropoietin receptor (EPOR), calcium channel, voltage-dependent, gamma subunit 6 (CACNG6), NLR family, pyrin domain containing 1 (NLRP1), platelet/endothelial cell adhesion molecule (PECAM1), nitric oxide synthase 1, activating transcription factor 3, keratin associated protein 8-1 (KRTAP8), glutamate receptor, ionotropic, kainate 5 (GRIK5), solute carrier family 24 member 3 (SLC24A3), solute carrier family 5 member 12 (SLC5A12), solute carrier family 10 member 2 (SLCA10A2), solute carrier organic anion transporter family, member 1A2 (SLCO1A2), solute carrier family 25 member 5 (SLC25A5), synaptophysin-like 2, neuroligin 2 (NLGN2), protein kinase, cAMP-dependent, catalytic, alpha (PRKACA), FBJ murine osteosarcoma viral oncogene homolog B (FOSB), ST3 beta-galactoside alpha-2,3-sialyltransferase 3 (SIAT6), lysyl oxidase-like 2 (LOXL2), perforin 1, ADP-ribosylarginine hydrolase (ADPRH), amyloid beta precursor protein-binding, family B, member 3 (APBB3), early growth response 3, cannabinoid receptor 2, interferon induced transmembrane protein 1 (IFITM1), phospholipase A2, group V (PLA2G5), calmodulin binding transcription activator 1 (CAMTA1), SRY (sex determining region Y)-box 4, nuclear factor I/B (NFIB), nuclear factor I/C (NFIC), RNA binding motif, single stranded interacting protein 1 (RBMS1), G0/G1 switch 2 (G0S2), FAT tumor suppressor homolog 3, solute carrier family 40 member 1 (SLC40A1), glypican 6 and insulin-like growth factor 1 receptor (IGF1R), and b) comparing said expression level measured in step a) with that measured in a control, said control being a cumulus cell surrounding an oocyte which, once fertilized, has produced a viable embryo associated with a high implantation rate leading to pregnancy; and c) assessing that said oocyte will not, once fertilized produce a viable embryo associated with a high implantation rate leading to pregnancy, if a differential expression between said oocyte and said control is measured at step b). a) measuring the expression level of 45 genes in a cumulus cell surrounding said oocyte, wherein said 45 genes are wingless-type MMTV integration site family, member 6, leucine-rich repeats and calponin homology domain containing (LRCH4), paired box 8, calcium binding protein 4 (CABP4), phosphodiesterase 5A, cGMP-specific (PDE5A), BCL2-like 11 (BCL2L11), phosphoenolpyruvate carboxykinase 1, transcription factor 20, SLAM family member 6 (SLAMF6), erythropoietin receptor (EPOR), calcium channel, voltage-dependent, gamma subunit 6 (CACNG6), NLR family, pyrin domain containing 1 (NLRP1), platelet/endothelial cell adhesion molecule (PECAM1), nitric oxide synthase 1, activating transcription factor 3, keratin associated protein 8-1 (KRTAP8), glutamate receptor, ionotropic, kainate 5 (GRIK5), solute carrier family 24 member 3 (SLC24A3), solute carrier family 5 member 12 (SLC5A12), solute carrier family 10 member 2 (SLCA10A2), solute carrier organic anion transporter family, member 1A2 (SLCO1A2), solute carrier family 25 member 5 (SLC25A5), synaptophysin-like 2, neuroligin 2 (NLGN2), protein kinase, cAMP-dependent, catalytic, alpha (PRKACA), FBJ murine osteosarcoma viral oncogene homolog B (FOSB), ST3 beta-galactoside alpha-2,3-sialyltransferase 3 (SIAT6), lysyl oxidase-like 2 (LOXL2), perforin 1, ADP-ribosylarginine hydrolase (ADPRH), amyloid beta precursor protein-binding, family B, member 3 (APBB3), early growth response 3, cannabinoid receptor 2, interferon induced transmembrane protein 1 (IFITM1), phospholipase A2, group V (PLA2G5), calmodulin binding transcription activator 1 (CAMTA1), SRY (sex determining region Y)-box 4, nuclear factor I/B (NFIB), nuclear factor I/C (NFIC), RNA binding motif, single stranded interacting protein 1 (RBMS1), G0/G1 switch 2 (G0S2), FAT tumor suppressor homolog 3, solute carrier family 40 member 1 (SLC40A1), glypican 6 and insulin-like growth factor 1 receptor (IGF1R), and b) comparing said expression level measured in step a) with that measured in a control, said control being a cumulus cell surrounding an oocyte which, once fertilized, has produced a viable embryo associated with a high implantation rate leading to pregnancy; and c) assessing that said oocyte will not, once fertilized produce a viable embryo associated with a high implantation rate leading to pregnancy, if a differential expression between said oocyte and said control is measured at step b).