… as well as being a strong influence to Florence Nightingale who pioneered modern nursing

Edit: to clarify, Quetelet seems to be mostly a polymath who was really interested in the “average men”; him developing the BMI reflects that interest, as BMI was originally used to find out weight/body type distributions among people (somewhat analogous to how IQ was originally developed for identifying students who needed additional assistance in classes). Quetelet never did anything related to Eugenics, but he did become a huge influence to Francis Galton, who… did the rest