Epidemiology
From Memory Alpha, the free Star Trek reference.
Epidemiology is the branch of medicine that deals with the incidence, distribution and control of disease in a population.
When B'Elanna Torres discovered, in 2377, that her unborn daughter was to possess many of the same Klingon features that Torres herself possessed, she began exploring several potential genetic modifications she could make to her fetus to make it less Klingon. In a discussion with the Doctor, she brought up several reasons why she felt her "preventive" changes were necessary, such as how her third lung could become diseased. To support her research she presented the Doctor with statistical analyzes and epidemiology. The Doctor agreed to look at it, however, still felt that there was "no valid medical reason to do what [she was] proposing." (VOY: "Lineage")
