How often do embryos get mixed up and put in the wrong person? What should I do if this has happened to me? What are my ethical and legal options?

V.V.

Laboratories use so much caution when working with sperm, eggs and embryos that this possibility should be virtually nonexistent. First, all plastic culture dishes and sample containers are labeled, so, the dishes clearly indicate whose embryos are being examined. The incubators now have separate shelves and "incubator rooms," with labels, to further minimize the risk. Laboratory workload is staggered so that only one patient's embryos are being examined at a particular time. And, finally, the paper trail follows each egg from the beginning of this process to the end, thereby accounting for each oocyte that is retrieved, fertilized, transferred and cryopreserved, as well as each that fails to develop and is discarded.

While these steps virtually eliminate the risk of transferring the wrong embryos by mistake, there are no ironclad guarantees. Unfortunately, a few years ago, an unscrupulous provider of infertility care believed he was doing good by transferring excess high-grade embryos to patients whose own embryos had a lower fertility potential. No system can prevent or avoid such malfeasance. However, labs are inspected by certifying organizations (including SART, JCAHO or CAP) that monitor systems and adherence to policies that have been put in place to avoid these situations.

As for testing, blood samples from both you and your husband as well as your baby should easily identify whether a mix-up has occurred. It is unlikely you will find your fears confirmed, but if testing indicates that the baby is not yours, I would suggest you consider first what is in the child's best interest. If you carried the pregnancy, the baby is legally yours, regardless of the genetic makeup of the sperm, egg or embryo. The contributors of sperm and egg can not come demanding they take "their" baby away from you. This is your baby.

If tests indicate there was a mix-up, you need carefully review your beliefs and parenting desires before making any decisions. Discuss your concerns with your physicians and your spiritual advisor as well as your lawyers. While a lawsuit may provide financial recompense, it comes at a great cost and can do nothing to correct the mistake.

Infertility treatment is a rapidly developing science. Initially, the science got a bit ahead of the ethical and legal issues that surround this field. But that is not the case today. Procedures are in place and standards have been adopted to prevent this tragic sort of error. It is unfortunate that the clinic with which you sought care was not able to provide the assurance and comfort that it adhered to the highest standards of care. Hopefully, the testing should provide reassurance that your baby is genetically yours.