Is a Fetus Alive?

Last week we saw the words of the Rambam, that the reason that the Mishna permits terminating a pregnancy when the mother's life is in danger is due to the law of rodef, the pursuer. If this is the case, then why does the Mishna forbid killing the half born child to save the mother, surely he is still considered a pursuer the entire time that the mother's life is in danger? The answer to this query on the Rambam can provide an answer as to the halachic status of the embryo; is he considered alive or not? 

Rabbi Eliezer Waldenberg tz"l, the late halachic giant of Jerusalem, the posek for Sha'arei Zedek Hospital and one of the experts in halacha and medicine, was asked whether one can terminate the pregnancy of a fetus who is suffering from a serious congenital condition. In this case the mother was not in any immediate danger and so the case was not analogous with that of the Mishna. Rabbi Waldenberg allowed a termination to be performed based on the Mishna and on his understanding of the Rambam. He claimed that the Rambam was of the opinion that the unborn fetus is not considered alive since he does not have independent life; but once he is born he is considered a full life. The question then remains as to why did the Rambam employ the principle of the rodef? Rabbi Waldenberg answers, quoting a response of the Nodeh Biyhuda, that even though the fetus is not seen in the eyes of the halacha as being alive, still it has the halachic category of a treifa, a living being that does not have independent life. While it is less severe to kill a treifa than killing a person, still it is not permitted. However, since the fetus is endangering the mother and is a rodef, it is permitted to terminate the pregnancy. This would be the same if the fetus was suffering from a serious condition that would be very difficult to treat, in certain cases this would be grounds to terminate the pregnancy. One question remains, how come the fetus is only a rodef until he is born? Rabbi Waldenberg answers that the Rambam did not mean he is a rodef only that this situation is similar to the case of the rodef. He is like a rodef but not really a rodef and thus not all the laws of rodef are applicable. This is not a simple answer since the Rambam brings in this case in the first chapter of the laws of murder where he discusses the laws of rodef and brings this as a prime example. If it is only similar to a rodef then why does he bring this as the example? Also Rabbi Waldenberg understands that the word rodef in the Rambam is a noun, where there is evidence that it may be a verb which changes the understanding of the sentence. Still, Rabbi Waldenberg holds that the unborn fetus is not considered alive. Next week, the other side of the dispute...