An interesting blog from Rick Lowery, Ph.D.
'Exodus 21:22-25 describes a case where a pregnant woman jumps into a fight between her husband and another man and suffers injuries that cause her to miscarry. Injuries to the woman prompt the normal penalties for harming another human being: an eye for an eye, a tooth for a tooth, a life for a life. Killing the woman is murder, a capital crime.
The miscarriage is treated differently, however — as property loss, not murder. The assailant must pay a fine to the husband. The law of a life for a life does not apply. The fetus is important, but it’s not human life in the same way the pregnant woman is.
My impression is that most Americans have a more nuanced and conservative view than the Bible does on this, though we’re getting at the same idea: an important moral and legal line is crossed when the fetus can survive outside the womb.
For the Bible, that’s when a child is born and starts breathing. For many of us today, it’s when a fetus becomes “viable” — somewhere between 21 and 27 weeks into the pregnancy, thanks to our amazing medical technology.
If something goes wrong late in the pregnancy and the fetus dies, we call it “still birth” and, by law, issue a death certificate.
If the pregnancy ends early on, we call it “miscarriage.” It’s traumatic, a terrible loss, but most of us think of it differently than we think of a still birth. We don’t require death certificates for miscarriages.
Recognizing this difference, the Supreme Court in Roe v. Wade created the “trimester” system to sort through the legal implications of the constitutional “right to privacy” they said we all have as Americans.
The justices ruled that the early and late stages of pregnancy are morally and legally distinct.
Early on, in the “first trimester,” the embryo undeniably is human life, but it’s not “a human being” in the normal sense of the term. At this stage of pregnancy, a woman’s right to privacy trumps any responsibility the state might have to protect the embryo by interfering with the woman’s decision to terminate the pregnancy.
Late in the pregnancy, certainly by the “third trimester,” however, the child has reached a stage of development that changes its moral and legal status. To protect the rights of the viable fetus, states can put serious limits on a woman’s right to abortion, though they must continue to respect her right to self-defense, to terminate the pregnancy to save her own life or prevent serious injury.
In the ambiguous middle of the pregnancy, the “second trimester,” the state has to balance the right to life of the unborn with the right to privacy of the woman, a balance that continues to tip toward the fetus as the pregnancy progresses. In this stage, our constantly improving medical technology plays an important role in the moral-legal equation.
Roe doesn’t require “abortion on demand” until the moment of birth. Rather, abortion is illegal in most states once the fetus is viable (normally 24 weeks into the pregnancy), unless it’s necessary to save the life of the mother or prevent serious physical or mental harm.
I think the moral reasoning of Roe and subsequent Supreme Court decisions reflects what many of us actually think: the moral status of the fetus changes over the course of the pregnancy.'