Clumps of cells were harvested from ePNT blastocysts for whole genome amplification followed by microarray-CGH analysis according to a previously validated protocol using 24Sure Cytochip (Illumina, Cambridge, UK). Cells were obtained from the TE, ICM or both. Lysis and whole genome amplification was performed using the SurePlex kit (Illumina) according to the manufacturer’s instructions. Samples from ePNT blastocysts were labelled with Cy3 while a commercially available reference 46,XY DNA was labelled with Cy5 (Illumina)32 (link). A laser scanner (InnoScan 710, Innopsys, Carbonne, France) was used to analyse the microarrays after washing and drying. The resulting images were analysed using BlueFuse Multi analysis software (Illumina).