Human embryonic stem cell (hESC) banks strive to establish hESC lines from discarded or surplus human embryos. The effect of embryo quality on establishing hESC lines was investigated by observing cultures derived from 28 Taiwanese fresh surplus and donated embryos that were cultured using the whole embryo method. Cultures of hESC lines were followed for 15 months. At the blastocyst stage, 14 of the 28 embryos were graded as good quality, defined as featuring a blastocoel volume of at least half of the embryo volume. Fourteen embryos did not meet these standards on day 5. Five successful hESC lines were derived from the good quality embryos (5/14; 35.7%); these hESC cells grew for 27–60 passages. In contrast, cells from poor quality embryos all stopped growing at the second or third passage. The successful hESC exhibited typical stem cell characteristics, including the capacity for pluripotent differentiation. Embryo quality on day 5, as defined by blastocoel volume, is thus a strong predictor for successful establishment of hESC lines
