Moving to blastocyst biopsy for preimplantation genetic diagnosis and single embryo transfer at sydney IVF  Kylie A de Boer, Ph.D., James W Catt, Ph.D., Robert P.S Jansen, M.D., Don Leigh, Ph.D., Steven McArthur, B.Sc.  Fertility and Sterility  Volume 82, Issue 2, Pages 295-298 (August 2004) DOI: 10.1016/j.fertnstert.2003.11.064

FIGURE 1 Human blastocyst-stage biopsy for preimplantation diagnosis. The zona is opened by laser on day 3 (A), which allows the developing trophectoderm to protrude after blastulation (B), facilitating biopsy (C). The embryo is left largely intact and is able to be cryostored (D) without loss of inner cell mass (ICM), while a cluster of trophectoderm (TE) cells is available for genetic analysis (E), often revealing apparently physiological tetraploidy (F). de Boer. Blastocyst biopsy for PGD. Fertil Steril 2004. Fertility and Sterility 2004 82, 295-298DOI: (10.1016/j.fertnstert.2003.11.064)