There are various grounds cited for opposing abortion; religious, moral, etc.  Religion and morals, however, vary from individual to individual, and the law is expected to be neutral with respect to particular religious and moral points of view.  One bedrock issue in the United States, however, is equal protection under the law.  If a pregnant woman is injured, either deliberately or through the callous disregard of another person, causing the death of her unborn child, the legal system prosecutes the actor for murder of the child.  However, if the pregnant woman chooses to end the life of her unborn child, the death of that child is not a crime at all.  The state then either does not consider the most basic right of a human being worthy of protection, or knowingly prosecutes people for murder when no murder has taken place.  One or the other is very wrong.  The inconsistency in the law is inherently absurd.  Not to make light of a serious issue, but consider the following: if a pregnant woman goes to Planned Parenthood to abort her unborn child, and is punched in the abdomen while in the waiting room, resulting in the death of the child, should the assailant be charged with homicide in addition to assault, or with practicing medicine without a license?  While you might consider that example silly, it is no sillier than the inherent contradiction that has been inserted into US law since 1973.