Array CGH has been adapted to accurately detect chromosomal imbalances including trisomy 13, 18, and 21, as well as monosomy X, from single lymphoblasts, fibroblasts, and blastomeres within a single day. This represents a significant advancement over previous metaphase CGH methods, which were labor-intensive and time-consuming. The technique allows genome-wide aneuploidaneuploidy screening from individual cells with high resolution and is amenable to automation. [@le_caignec_single-cell_2006]