MR. JUSTICE BLACKMUN delivered the opinion of the Court.

We forthwith acknowledge our awareness of the sensitive and emotional nature of the abortion controversy, of the vigorous opposing views, even among physicians, and of the deep and seemingly absolute convictions that the subject inspires. One’s philosophy, one’s experiences, one’s exposure to the raw edges of human existence, one’s religious training, one’s attitudes toward life and family and their values, and the moral standards one establishes and seeks to observe, are all likely to influence and to color one’s thinking and conclusions about abortion.

In addition, population growth, pollution, poverty, and racial overtones tend to complicate and not to simplify the problem.

Our task, of course, is to resolve the issue by constitutional measurement free of emotion and of predilection. . . . We . . . place . . . some emphasis upon medical and medical-legal history and what that history reveals about man’s attitudes toward the abortive procedure over the centuries. We bear in mind, too, Mr. Justice Holmes’ admonition in his now vindicated dissent in Lochner v. New York (1905):

It [the Constitution] is made for people of fundamentally differing views, and the accident of our finding certain opinions natural and familiar or novel and even shocking ought not to conclude our judgment upon the question whether statutes embodying them conflict with the Constitution of the United States.

The usual rule in federal cases is that an actual controversy must exist at stages of appellate or certiorari review, and not simply at the date the action is initiated.

But when, as here, pregnancy is a significant fact in the litigation, the normal 266-day human gestation period is so short that the pregnancy will come to term before the usual appellate process is complete. If that termination makes a case moot, pregnancy litigation seldom will survive much beyond the trial stage, and appellate review will be effectively denied. Our law should not be that rigid. Pregnancy often comes more than once to the same woman, and in the general population, if man is to survive, it will always be with us. Pregnancy provides a classic justification for a conclusion of nonmootness. It truly could be "capable of repetition, yet evading review. . . ."

It perhaps is not generally appreciated that the restrictive criminal abortion laws in effect in a majority of States today are of relatively recent vintage. Those laws, generally proscribing abortion or its attempt at any time during pregnancy except when necessary to preserve the pregnant woman’s life, are not of ancient or even of common law origin. Instead, they derive from statutory changes effected, for the most part, in the latter half of the 19th century.

Three reasons have been advanced to explain historically the enactment of criminal abortion laws in the 19th century and to justify their continued existence.

It has been argued occasionally that these laws were the product of a Victorian social concern to discourage illicit sexual conduct. Texas, however, does not advance this justification in the present case, and it appears that no court or commentator has taken the argument seriously. The appellants and amici contend, moreover, that this is not a proper state purpose at all and suggest that, if it were, the Texas statutes are overbroad in protecting it since the law fails to distinguish between married and unwed mothers.