Did you see the Sunday night Dateline on the couple who carried another couples baby to term after an IF clinic placed the wrong embryo in the woman in MI (!!) and it took? The RE clinic said it was due to 'human error' which of course is very scary but I can see how it can happen. At our clinic, the nurse AND the RE has you approve the name on the vile of sperm before it's inserted in the cathedar (and cathedar into you). But you're taking a huge leap of faith that the vile has the correct sperm in it.
If you didn't see it, you can view it HERE. Pretty interesting and such a blessing that the couple that received the wrong embryo carried the baby to term.