I agree with you that the current distinction between "conception" and "pregnancy" is not significant as to the moral status of the human embryo during the first two weeks of his or her new little life.
"Pregnancy" was defined by the American Medical Association and the American College of Obstetrics and Gynecology as beginning at the initial union of sperm and egg, i.e. fertilization, until 1965. It was after a series of interactions between the AMA, AACOG, the Population Council, and Planned Parenthood regarding birth control and the "population explosion" that the physician's groups chose to modify their definitions.
Following is a list of materials that document the change in terminology:
Dr. Mary Calderone, discussion, Mechanisms of Contraceptive Action," in Intrauterine Contraceptive Devices: Proceedings of the Conference, held April 30-May 1, 1962, New York City, ed. C. Tietze and S. Lewitt, published by Excerpta Medica Foundation, 110.
Sybil Meloy, "Pre-Implantation Fertility Control and the Abortion Law," Chicago- Kent Law Review, vol. 41 (1964): 183, 205-06. Planned Parenthood recognized in its amicus brief for Roe v. Wade that criminal abortion laws could be applied to the IUD because of its potential to prevent implantation. PPFA its physician group (APPP) Amicus brief on page 44 cited Cybil Meloy, and also said that prosecutors had not used state anti-abortion laws to outlaw the use of IUD's.
Abraham Stone, M.D., "Research in Contraception: A Review and Preview," presented at the Third International Conference of Planned Parenthood, Bombay, India Report of the Proceedings, November 24-29, 1952, no copyright, Family Planning Association of India, 101.
A Survey of Research on Reproduction Related to Birth and Population Control (as of January 1, 1963) US Department of Health, Education, and Welfare, Public Health Service, page 27.
Memo to Dr. Drill from Dr. Saunders, re: "Effects of Drugs on Mating in Rats," 12/9/54, Gregory Pincus Papers, Manuscript Division, Library of Congress; Abraham Stone, The Control of Fertility, Scientific American, April, 1954, vol. 190., no. 4, 31-33.
Bent Boving, "Implantation Mechanisms," in Mechanisms Concerned with Conception, ed. C. G. Hartman (New York: Pergamon Press, 1963), 386. Boving acknowledged (p. 321): "... the greatest pregnancy wastage, in fact, by far the highest death rate of the entire human life span, is during the week before and including the beginning of implantation, and the next greatest is in the week immediately following."
Proceedings of the Second International Conference, Intra-Uterine Contraception, held October 2-3, 1964, New York City, ed. Sheldon Segal, et al.., International Series, Excerpta Medica Foundation, No. 86, page 212.
ACOG Terminology Bulletin, Terms Used in Reference to the Fetus, Chicago, American College of Obstetrics and Gynecology, No. 1, September 1965.
Dr. Richard Sosnowski, head of the Southern Association of Obstetricians and Gynecologists "The Pursuit of Excellence: Have We Apprehended and Comprehended It?" American Journal of Obstetrics and Gynecology, vol. 150. No. 2 (September 15, 1984) 117.
Wow. Great post.
No surprise here. Leftists ALWAYS manipulate vocabulary to make it "compatible" with their desired political positions---ALWAYS.