Professor Churchill earned his Ph.D. from Harvard University in 1967. His research has been especially devoted to the German biologist August Weismann (1834-1914), whose biography he is preparing. He has edited two books:
- Leonidas J. Blacher, The Problem of the Inheritance of Acquired Characters: A History of A Priori and Empirical Methods Used to Find a Solution, trans. from Russian by Noel Hess. Washington, D.C.: The Smithsonian Institution, 1982.
- with Helmut Risler. August Weismann: Ausgewahlte Briefe und Dokumente, Selected Letters and Documents, 2 vols. Freiburg i. Br.: Universitätsbibliothek, 1999. [Schriften der Universitaets-bibliothek, Freiburg im Breisgau, Band 24, 1&2.]
He has published numerous articles in the history of heredity, development, and evolution:
- "August Weismann and a Break from Tradition," Journal of the History of Biology 1 (1968): 91–112.
- "From Machine Theory to Entelechy: Two Theories in Developmental Teology," Journal of the History of Biology 2 (1969): 165–185.
- "An Essay Review: The History of Embryology as Intellectual History," Journal of the History of Biology 3 (1970): 155–181.
- "Hertwig, Weismann and the Meaning of Reduction Division," Isis 61 (1970): 429–457.
- "Chabry, Roux and the Experimental Method in Embryology," in Methodological Foundations of Science: The Nineteenth Century, Bloomington: Indiana University Press, 1973, pp. 161–205.
- "Wilhelm Johannsen and the Genotype Concept," Journal of the History of Biology 7 (1974): 5–30.
- "The Modern Evolutionary Synthesis and the Biogenetic Law," (1974) in Proceedings of a Workshop on the Evolutionary Synthesis Held at the American Academy of Arts and Sciences, ed. by Ernst Mayr and William Provine, Cambridge, Mass: Harvard, 1981, pp. 112–122.
- "Rudolf Virchow and the Pathologist's Criteria for the Inheritance of Acquired Characteristics," Journal of the History of Medicine 31 (1976): 117–148.
- "The Weismann-Spencer Controversy over the Inheritance of Acquired Characters," Human Implications of Scientific Advancement. Proc. of the XV Int. Congress for the History of Science, ed. by Eric G. Forbes, Edinburgh Univ. Press, 1977, pp. 451–468.
- "Sex and the Single Organism: Biological Theories of Sex in Mid Nineteenth Century," Studies in the History of Biology 3 (1979): 139–177.
- "In Search of the New Biology: An Epilogue," Journal of the History of Biology 14 (1981): 177–191.
- "Darwin and the Historian," Biological Journal of the Linnaean Society 17 (1982): 45–68.
- "Weismann's Continuity of the Germ Plasm in Historical Perspective," in August Weismann (1834–1914) und die theoretische Biologie des 19. Jahrhunderts, ed. by Klaus Sander, Freiburger Universitätsblätter, 1985, 87/88: 107–124.
- "Weismann, Hydromedusae, and the Biogenetic Imperative: A Reconsideration," in T. J. Horder, J. A. Witkowski, and C. C. Wylie (eds.), History of Embryology, Cambridge: Cambridge University Press, 1986, pp. 7–33.
- "From Heredity Theory to Vererbung: The Transmission Problem, 1850–1915," Isis 78 (1987): 337–364.
- "Introduction: Toward a History of Protozoology," J. Hist. Biol. 22 (1989): 185–187.
- "The Guts of the Matter: Infusoria From Ehrenberg to Bütschli, 1838–1876," J. Hist. Biol. 22 (1989): 189–213.
- "The Rise of Classical Descriptive Embryology" in A Conceptual History of Modern Embryology, ed. by Scott Gilbert, New York: Plenum Press, 1991, pp. 1–29.
- "Regeneration, 1885–1901," in A History of Regeneration Research: Milestones in the Evolution of a Science, ed. by Charles E. Dismore, Cambridge: Cambridge University Press, 1991, pp. 113–131.
- "An Analysis of Julian Huxley and Gavin de Beer's Elements of Embryology," in Julian Huxley: Biologist and Statesman of Science, ed. by C. Kenneth Waters and Albert Van Helden, Rice University Press, 1993, pp. 107–126.
- "On the Road to the k Constant: A Historical Introduction," in Julian Huxley, Problems of Relative Growth, Repr., Baltimore: Johns Hopkins University Press, 1993, pp. xix-xlv.
- "Life Before Model Systems: General Zoology at August Weismann's Institute," American Zoologist 37 (1997): 260–268.
- "Shifting the Boundaries of Moral Behavior: The Case of Alfred Kinsey," Journal Korean Bioethics Association, 1 (2000): 163–178.
- "August Weismann: A Developmental Evolutionist," in Churchill and Risler (1999), vol. 2, pp. 749–798, see above.
- "August Weismann and Ferdinand Dickel: Testing the Dzierzon System," in Science, History and Social Activism: A Tribute to Everett Mendelsohn, ed. by Garland Allen and Roy MacLeod, Dordrecht, Boston, London: Kluwer Academic Publishers, 2001.
- "The Evolutionary Ethics of Alfred C. Kinsey," Hist. & Phil. of the Life Sciences 24 (2002): 391–411. Reprinted with two new illustrations in Scientific Values and Civic Virtues, ed. by Noretta Koertge, Oxford University Press, 2005.