Another aspect important to an historical analysis of abortion is that there was widespread disapproval and prohibition of abortion during early pregnancy before, in the view of the science of the time, human life had been infused. Our ancestors’ biologically incorrect notions of when human life begins led Blackmun to assert that, historically, “abortion was viewed with less disfavor than under most American statutes currently in effect” (in January, 1973) and “[p]hrasing it another way, a woman enjoyed a substantially broader right to terminate a pregnancy than she does … today.”
Regarding this important question, scholarly research reveals that recognition of the unborn as “persons in the whole sense” was largely determined by the biological and medical knowledge of each historical era. The ovum and the actual nature of fertilization were not discovered until the nineteenth century, and prior to this, scientists and contemporaneous jurists supposed that human life commenced at “formation,” “animation,” or “quickening.” Abortion was seen as unquestionably homicidal only after the gestational point at which, in light of the science of the time, human life was finally understood to be present. 
Many legal scholars have pointed out that other areas of law, such as torts property and criminal law, all recognize the unborn child as a person with legal protections under the law.
[M]edical authority has recognized long sense that the child is in existence from the moment of conception, and for many purposes. It existence is recognized by the law. The criminal law regards it as a separate entity, and the law of property considers it in being for all purposes which are to its benefit, such as taking by will or dissent… All writers who discuss the problem have joined in condemning the old rule, and maintaining that the unborn child out of an automobile is as much a person in the street as the mother. 
In reference to property law, in 1941, a New York Court stated: “it has been the uniform and unvarying decision of all common law courts in respect of the state matters for at least the past two hundred years that a child en ventre sa mère (in its mother’s womb) is ‘born’ and ‘alive’ for all purposes for his benefit.”
The rules of property law have not changed, and pre-born children are still afforded their just legal protections. If property law recognizes the rights of a child in its mother’s womb, it makes no sense that the court would deny them, especially since property was not the only area of law in which those rights were recognized.
By 1971, twenty-nine states and the District of Columbia allowed suits for prenatal injuries based on tort law, and an additional nine rejected the viability distinction and allowing recovery. In 1953, a New York State appellate court found that:
We ought to be safe in this respect. In saying that legal separability should begin where there is biological separability. We know something more of the actual process of conception and foetal development now than when some of the common-law cases were decided; and what we know makes it possible to demonstrate clearly that separability begins at conception.
This rationale was also stated by the Pennsylvania Supreme Court in 1960:
As for the notion that the child must have been viable when the injuries were received, which is claimed the attention of several of the states, we regard it as having little to do with the basic right to recover, when the foetus is regarded as having existence as a separate creature from the moment of conception.
Today, only three states do not provide tort claims for prenatal injuries, nearly 3 thirty states allow for recovery at any point in the pregnancy. This is yet another example of the schizophrenic nature of the Supreme Court denying pre-born children recognition under the law, when the law of torts clearly recognized their rights.
In criminal law, the quickening distinction was dropped my most a legislatures by the 1860s as medical science progressed, and today thirty-eight states have abolished the born alive rule in the lower prosecution for fetal homicide at any time in the pregnancy.him him
Justice Blackmun, writing for the court in Roe, stated that the court did not need to decide the “difficult” question of when life begins, but this is the most important question to be decided. Because it is not the courts job to decide what philosophy or religion is correct, it must be scientific fact which dictates who is covered by the Constitution. There is no doubt that human life begins at conception (also called fertilization), and even the most cursory glance into the science of fetal development would confirm this fact. The court gave no rationalization for why a human and a person were separate entities, that required separate legal protections under the law, and many have criticized this distinction as similar to the one the Court made in Dred v Scott.
 Roger Resler, Compelling Interest, page 19 – 30
 Compelling Interest, page 26
 Prof. William Prosser Law of Torts at 335.
 In re Holtenhausen’s Will, 175 Misc. 1022, 26 N.Y.S.2d 140 (NY Surr. Ct. 1941).
 Abuse of Discretion , page 275
 Kelly v. Gregory, 282 App.Div. 542, 125 NYS.2d 696, 697 (1953).
Sinkler v Kneale, 401 Pa. 267, 164 A.2d 93, 96 (1960)
 Abuse of Discretion, page 283 figure 7.
 Abuse of Discretion, page 284-5 figure 9.
 See e.g. http://www.princeton.edu/~prolife/articles/embryoquotes2.html (a compilation of quotes from recognized medical textbooks and authorities, on when human life begins)
 See e.g Compelling Interest, page 20; Justice Scalia’s dissent in Planned Parenthood v. Casey at 998