Juvenile calf oocytes represent an untapped source of germ plasm for reproduction. Reports on the developmental competence of calf oocytes have been controversial. In this research, oocytes were recovered after gonadotropin stimulation from Holstein calves (N = 10) at 2-3 mo of age (2-mo cycle) and again at 4-5 mo of age (4-mo cycle). The in vitro developmental competence was measured, and prestimulation follicle numbers (for 2-mo cycle) and poststimulation follicle numbers (both cycles) were obtained. The number of antral follicles doubled after stimulation (23.4 +/- 6.1 vs. 55.1 +/- 16.1) for the 2-mo cycle and for the 4-mo cycle (47.4 +/- 12.4). The number of follicles observed prior to stimulation in the 2-mo cycle was found to be highly correlated with the poststimulation oocyte recovery for both collection cycles (r = 0.95, 2-mo cycle; r = 0.81, 4-mo cycle). The majority (90-96%) of recovered oocytes were found to be usable for in vitro maturation and fertilization; of these, 41-42% cleaved and 10-11% developed to morulae or blastocysts. Eighty-four in vitro-produced embryos were transferred to synchronized recipients and resulted in 11 pregnancies, leading to 7 live (4 males, 3 females) and 2 dead (one male, one female) calves at full term. No significant differences were observed between the 2-mo and 4-mo collection cycles; however, 73% of the total pregnancies resulted from the 2-mo cycle. All pregnancies resulted from embryos of high-responding donors. The high correlation between the number of follicles prior to stimulation and the poststimulation response suggests the possibility of screening calves prior to stimulation for routine embryo production.

Patients' conceptualization of their embryos plays an important role in embryo disposition decisions. Our research showed that patients deal with these decisions in a two-stage decision sequence.

This study showed a positive trend in donation for science and a negative trend in donation to others and discarding. A substantial number of individual patients chose different types of EDDs in consecutive mailings, which shows that advance EDD directives should be used with caution.

Interviews were conducted with patients undergoing treatment at the department for reproductive medicine at the University Hospital of Ghent, Belgium to describe how patients think about the use of embryos for science and how patients' views are related to their decision whether or not to donate their supernumerary embryos for science. Most participants knew little about the use of embryos for science. The perception of science and scientists, rather than the perception of the embryo, played an important role in the disposition decision making. The feeling of not having control over what would happen to their embryo and the fear that scientists would allow their embryo to develop into children were the main arguments against donation. This showed the importance of information about scientific research with embryos, such as the 14-day limit to keep embryos alive. Half of the participants pictured the medical team as the requesting party for their embryos and those who were not willing to donate indicated that they could be persuaded when asked directly by their caregivers. In conclusion, this study suggests that the perception of science, rather than the perception of the embryo, plays an important role in the decision to donate for science.

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