The "Jewish" view on abortion varies based on the stream of Judaism which is answering, although there are some commonalities. I will address those first and then give the basis for the dissents. (There is a nice summary of the halacha in an article by Daniel Eisenberg here - http://www.jewishvirtuallibrary.org/jsource/Judaism/abortion.html.)
First, Judaism regards the life of the mother as a priority in all cases. A fetus which is a danger to the mother is considered a rodef - one who is pursuing with intent to harm, and therefore even lethal means are acceptable to save the one being pursued. Second, Judaism considers the fetus as a part of the mother, subject recovery for property damages, until midway through the birth process. All streams of Judaism recognize the uniqueness of each life, the sacred nature of the act of conception, and the potential of life as important. However, once the issue moves to consideration of defects of the fetus, ability to raise the child, difficulty in carrying through to gestation, or desire for a child, different streams have different answers. As Eisenberg states, some Orthodox poskim (halakhic authorities)do not even permit amniocentesis while others permit abortion in the case of the discovery of a fatal disease (such as Tay Sach's) even into the second trimester. The Reform movement's position can be obscured by its political stance, which is that the decision is personal and should not be dictated by the government - the right to seek an abortion should be available to all, whether or not Reform Judaism practice condones particular cases for particular women. (Rabbi Jonathan Biatch details the Reform position quite well here - http://urj.org/ask/questions/abortion/.)
If one could sum up, the Jewish view on abortion is that there is a value to all human life, even in potential, which should be weighed in any decision.
As to the question of a child conceived (or even born) out of wedlock, the answer is much simpler. There is no Jewish consequence to a child being born out of wedlock. Mamzerut, the Jewish equivalent to bastardy, attaches only to the child of a prohibited liaison - such as the child of an adulterous relationship (one of the parties is married), or the child of a cohen (preistly family) and a divorcee, etc. Mamzerut is not a relevant category in Reform Judaism, but does have ramifications in the Orthodox world and for marriage and other religious and civil rights (such as burial) in Israel. (A good reference is this citation of the Encyclopedia Judaica article by former Israeli Chief Justice Menahem Elon - http://urj.org/ask/questions/abortion/.)
A proper response requires that the question be limited in scope for it is too general for practical consideration. Jewish law under certain conditions prohibits abortions and in other cases may even mandate abortions. Accordingly, no one may be able to state any clear cut general position. In order to solicit a realistic and pragmatic response it is necessary, therefore, to frame the question in a more limited manner.
One such concern would be to assess whether Jewish law agrees with the legal decision of the Supreme Court in Roe vs. Wade (1973). In this case, the Supreme Court ruled that within the first trimester of pregnancy women have the right to terminate an embryo or fetus within them. It, moreover, clearly contends that women are under no requirement to provide medical or other compelling reasons to permit the abortion. Women simply have the authority and discretion within the first trimester to abort a fetus. Jewish law, however, disagrees with the above position. Women are not granted such authority. Abortion on demand is simply prohibited. Without extenuating circumstances the rabbinate does not condone abortion. Though this is the consensus ruling of halachic scholars, it is not clear as to whether this prohibition is a Biblical or rabbinic ruling.
One sage in the Talmud, Rav Yishmael, even suggests that Scripture itself is the source for prohibiting indiscriminate abortions. It is written, “Whoso sheds man’s blood by man shall his blood be shed”. (Genesis 8:6- The Holy Scriptures, Koren Publishers)Of interest, is that the actual Hebrew text does not state that the action was performed “by man”. It, rather, says that it was “B’adam” [in man or , rather, in one’s body].-. Literally it means the shedding of blood occcurred in the person’s body. Rav Yishmael, therefore, contends that the meaning of a body in the body of another, relates to the abortion of a fetus which is prohibited.(Sanhedrin 57b) Others, do not consider such a Biblical interpretation as logically compelling. What is clear is that whether the prohibition is Biblical or rabbinic the consensus is to outlaw abortions unless there are extenuating circumstances.The Talmud, for example,rules that one may violate the Shabbat to save the fetus of a woman who died in childbirth. (Arachin7b) This overtly demonstrates the high regard held of the religious importance of preserving and protecting a fetus.This law does not define a fetus to be a living being. It merely notes that a fetus which will develop into a live person must be protected.
A brief case by case analysis will shed light on Halachic reactions to specific issues.
1.In the event that the mother’s life is deemed to be in jeopardy due to her pregnancy, Jewish law mandates the termination of the fetus to save the life of the mother.(Ohalot 7:6) It is evident that had the mother not had a life threatening condition, the termination of the fetus would have been prohibited.
2. Should a fetus be defective, there is rabbinic disagreement as to whether it is permissible to abort the fetus. Rav Moshe feinstien rules that it is forbidden to terminate the pregnancy contending that defective children have a right to live. Accordingly, he prohibits aborting the pregnancy of a mother who has been determined that she will give birth to a Tay Sachs child. HaRav Feinstien is of the firm belief that the abortion of such pregnancies is a serious immoral violation of Jewish law.(See “Aborting A Jewish Fetus”, Kuntras L’Torah V’Hora’a, Choveret 7, p.9,Elul 5’737) A contrary lenient position was ruled by Rabbi Eliezer Waldenberg. He felt that the severity of the ramifications of the Tay Sachs disease, namely, stunted physical and mental development followed by inevitable death by the age of four, mandated Halachic scholars to be lenient. As such, he permitted abortions in such cases to be performed until the seventh month of pregnancy.(Responsa Tzitz Eliezer, Vol.13:102)
3. May a woman who was raped abort her pregnancy? Rav Benzion Uziel, Sefardi Chief Rabbi of Israel, alongside Rav Kook, ruled that it is permissible to abort the pregnancy of a women raped to protect her from shame and humiliation.(Mishpatai Uziel,Vol.III,Choshen Mishpat, 46)
4. May the fetus of a Mamzer, a bastard or a child born in wedlock be aborted? (It is important to note that according to Jewish law a Bastard, a Mamzer is not a child of wedlock. It is , rather , a child born from incest or adultery.) Rav Moshe Feinstien rules that it is forbidden to abort such a child as well as a child of wedlock. (op.cit.,) According to RavUziel, it is permitted to avoid shame.(op.cit.,) Rav Yaakov Emdin ruled that it was permitted to abort a married woman made pregnant through adultery for the child would be classified as a Mamzer but not a child of wedlock for such a child has no stigma. (She’lat Yaviz 1:43)
5. In Nazi concentration camps it was ordained that all pregnant women were to be put to death.Were such women permitted to abort their pregnancy? Rabbi Efraim Oshry ruled that it was permissible to save the lives of the women. (Tashbez, pt3, No.2)
6 May an abortion be performed to prevent a nervous breakdown or mental problems to a mother? Those rabbis that disallow an abortion to women raped or claiming that a live birth will generate shame, also do not consider mental anguish as an Halachic excuse for an abortion. Those rabbis that deem shame to a mother as reason to permit abortions are lenient in terms of mental problems.
A firm belief in the near-absolute sanctity of life in Judaism is apparent in all sectors of Jewish law. Therefore, it should be no surprise that in regard to abortion Jewish law is no different. However, in applying such a principle to abortion, the crucial question becomes, when does life actually begin? On this matter Jewish tradition seems clear -- the Talmud tells us that full life only begins at birth. In other words, while obviously a fetus could represent the potential for life, in a legal and ethical sense a baby is only treated as a full living being when it is born. That being the case, abortion cannot be equated with murder and thus the more stringent legal/ethical arguments against abortion cannot be used in traditional Jewish legal discourse. In fact, due to the primacy placed on the sanctity of life, abortion may even be mandated in cases when the pregnancy endangers the life of the mother. This is because the full life of the mother takes priority over the potential life of the unborn child. Over time many rabbis have even included mental and emotional health concerns in regard to the mother as potential justification for allowing or mandating an abortion. Further, there is a distinction made between the first forty days of gestation and the time period beginning the forty-first day. This distinction means that legally the justification for abortion before the forty-first day need not be as stringent as justification required for an abortion after.
However, despite Judaism's distinction between life and potential life, Jewish tradition also recognizes the sanctity of potential life in real way. In that regard, abortion is not looked upon as completely discretionary or as acceptable in every circumstance. As a matter of both theology and law, Jewish tradition holds that our bodies are not completely our own -- they are gifts from God. As such our conduct toward our bodies needs to conform to Jewish law and therefore we may not cause our bodies harm. While, as a matter of politics, we may not want the US government to make the laws in this arena for us, traditional Jewish support for the Pro-Choice movement should not be taken to mean that ethically all decisions to abort made by individual women, or specific families, in particular cases are ethically correct. Cases which include children who will be born out of wedlock, children who will be born with known severe disabilities, children who will be born as a result of unwanted pregnancies, all present complicated scenarios that many rabbis have chosen to address individually -- one by one. However, according to my understanding of Jewish law, all such decisions revolve around the determination of whether such pregnancies will cause harm to another's life, however one chooses to definte that phrase.