13. Patrick Steptoe (known also for his work on in-vitro fertilization)

Patrick Steptoe was a British gynecologist best known for his pioneering work in in-vitro fertilization (IVF). In the 1960s and 1970s, he collaborated with embryologist Robert Edwards to develop techniques that allowed human eggs to be fertilized outside the body and then implanted in the uterus. Their breakthrough led to the birth of the first "test-tube baby," Louise Brown, in 1978. Steptoe's contributions to reproductive medicine have profoundly impacted infertility treatment, providing hope to countless couples struggling to conceive. His work has opened the door to advanced reproductive technologies used widely today.