Full-sibling embryos created by anonymous gamete donation in unrelated recipients.

OBJECTIVE To report the rare occurrence of full-sibling embryos in unrelated women using independently chosen donor sperm and donor oocytes in two different cycles unintentionally created at our IVF program, and to discuss the concept of disclosure to the patients. DESIGN Case report. SETTING Academic IVF program. PATIENT(S) Two women independently undergoing donor recipient cycles with anonymous donor oocytes and donor sperm. INTERVENTION(S) Both women received oocytes from the same donor several months apart and then by coincidence selected the same anonymous sperm donor to create anonymous full-sibling embryos. MAIN OUTCOME MEASURE(S) Clinical pregnancy after donor-recipient IVF cycle. RESULT(S) Both women conceived using the same donor sperm and donor oocytes in independent cycles, resulting in simultaneous pregnancy of full siblings. CONCLUSION(S) As providers with the knowledge that anonymous full sibling embryos have been created, we may have an obligation to disclose this information to the patients.