The use of frozen embryos
The same study from SART and the RAND corporation reported the different uses for frozen embryos (FE):
'patient treatment' was most common (87%)
destruction, over 2.2%
'research', over 2.8%
since research necessarily involves destruction, over 5% of FEs are destroyed.
Some embryos are used for 'quality assurance activities' (whatever that means) and some were even used for 'embryology training'.
It gets worse. The 2007 report from the CDC on ART has the statistics on clinics in the U.S. (Clinics are required by law to report)
They typically implant 2 or 3 embryos in the woman. The odds are that the vast majority of embryos, fresh or frozen, do not survive to birth.
The best case is a donor egg from a young healthy woman, fresh not frozen; 2 or 3 embryos are transfered and at least one child is born 55% of the time. This means that 45% of the time all 2 or 3 embryos died. Within the 55%, often 1 or 2 of the 2 or 3 transferred embryos die. So the percentage of transferred embryos that die is well over 50%. There is insufficient data reported for determining the exact number or percentage of embryo deaths.
With frozen embryos from a young healthy donor, the percentage of transferred sets of embryos that result in at least one child born is 31.9 percent. Again, this does not account for the fact that 2 or 3 embyros are typically transferred, but only one live birth is needed to count toward the 31.9% 'success' rate. The percentage of embryos that survive is probably half or less than the reported 31.9%. But all this is from a healthy young donor.
When the source of the egg is the woman who wishes to bear the child, she may be older, she may have medical problems resulting in infertility.
When nondonor eggs are used and the woman is in her 40s, they use more embryos for transfer and the percentage is nevertheless as low as 15 to 20%. Again, the percentage of surviving embryos is probably less than half or less than 1/3rd of this number.
Conclusion: The number of frozen embryos in the U.S. is likely greater than 450,000, and the number worldwide is probably between one half million and one million. The vast majority of these frozen embryos die without being born.
Roman Catholic theologian