A mix-up at the Herzliya Medical Center involving three women whose ova were fertilized by the wrong donated sperm could have been prevented if the women had asked for supervision of the in-vitro fertilization by experts from Jerusalem's Puah Institute. A routine examination at the private hospital in Herzliya on Friday showed that fertilized ova were apparently exposed to sperm from another man. Last week, three women came to the center to have their ova fertilized via micromanipulation, in which individual sperm are inserted into ova in a tiny hole in the outside "crust" created by a chemical or physical process. This process is required if the sperm are not very motile. The hospital staff themselves discovered the human error, in which the ova were placed in a Petri dish containing motile sperm from another donor. The three women and their partners were advised by the hospital against implanting the resulting embryos. The couples will decide within a few days whether the embryos will be disposed of or whether they will go through with implantation. If they decide the former, they will have to go again through the process of ripening ova with drugs, removing them surgically and having them fertilized with the partners' sperm. The Health Ministry was informed immediately of the mistake, and officials asked to see the internal investigation report from the hospital. "When we receive this material," the ministry said, "we will decide if there is a need for further investigation." Such errors can be prevented when the non-profit Puah Institute - which provides IVF supervisors throughout Israel - had been hired by the couples to supervised the fertilization and embryo implantation process. Since its establishment 17 years ago, the institute has caught dozens of errors that would otherwise have led to women giving birth to babies produced from sperm and/or eggs from another couple. Puah supervisors offer their services at the Herzliya hospital, but only to those who ask for and pay for it. In the three cases, Puah supervision was not requested. Rabbi Gideon Weitzman, head of English-speaking department of the Puah Institute, said that it offers IVF supervision at the Herzliya Medical Center for clients who want it at a cost of about NIS 360. However, the three women in this case did not request supervision. The institute (www.puah.org.il), named for the midwife mentioned in the Bible as surreptitiously delivering (with Shifra) doomed Israelite babies in Egypt, is claimed to be the only one of its kind in the world. The Orthodox Jewish institute is motivated by the need to prevent the birth of bastards, as babies produced from ova of a married woman not married to the man who gave the semen are considered mamzerim (bastards, who cannot marry Jews unless they are mamzerim themselves). Besides its Jewish clientele, it also serves Muslim, Christian, and other couples as well who want their IVF to be carried out without any errors.