James Young Simpson (born June 7, 1811 in Scotland) was a qualified doctor by the age of 21 but changed to work as a clerk, due to his traumatic reaction to witnessing mastectomies during his medical training. He sat in several lecture courses as a student, but the anatomical lecture by a Doctor Knox made him choose the career path of midwifery and obstetrics. He became a qualified professor of midwifery at the age of 29, in 1840.