ABSTRACT
Cleavage-stage embryo biopsy of single blastomeres allows the analysis of male and female genetic contribution to the nal embryo, by means of polymerase chain reaction (PCR) or uorescence in situ hybridization (FISH) analysis at the single-cell level. One or two blastomeres are removed from the embryo in the morning of Day 3, at about 68-72 hr after microinjection. The embryos are preferably in the third mitotic division, presenting at least ve cells or, more ideally, eight cells or more. Enough time for genetic or chromosomal testing is available if blastocyst transfer is performed on Day 5.
