Jean Frances Tatlock was born in Ann Arbor, Michigan, to John Strong Perry Tatlock, a renowned professor of medieval literature at the University of California, Berkeley, and Marjorie Fenton Tatlock, a writer and editor. Her early environment was intellectually stimulating, fostering a love for learning and critical thinking.

Jean spent her formative years surrounded by academics and intellectuals due to her father's profession. This exposed her to diverse ideas and cultivated a sophisticated worldview from a young age. The family moved between academic posts and residences depending on her father’s research.

Jean attended Vassar College, a prestigious women's college known for its academic rigor and progressive atmosphere. She excelled in her studies and developed a keen interest in literature, language and psychology. This period shaped her intellectual development and provided a platform for her to explore her intellectual curiosity. She may have begun to formulate her future career plans during this time.

After Vassar, Jean pursued pre-medical studies, demonstrating a desire to enter the medical field. This likely involved coursework in biology, chemistry, and other related sciences. This indicates a growing ambition to work in health and medicine.

Jean was accepted into Stanford University's medical school, a significant achievement. Her pursuit of a medical degree demonstrated her commitment to helping others and engaging with the scientific understanding of the human mind and body. This was an intensive period of study and clinical experience.