Genetics is the branch of biology concerned with the study of inheritance, including the interplay of genes, DNA variation and their interactions with environmental factors.
Genetics. Scientists have been studying how genetics influences human health for decades. We've made huge strides, but there's still much that we have yet to learn. The ultimate goal will be to have an increasingly strong understanding of which genetic variations can lead to disease, and the mechanisms through which those variations operate. Someday, the hope is that each individual patient's genetic information can help generate targeted advice about preventative and therapeutic actions they can take to maximize their health. It should be noted, however, that genetics are only one way in which health can be influenced; environment, behaviors, and other outside factors can be equally important.
NHGRI Bioethics Core