PBS | 8:00 pm

The new feature-length documentary "Human Nature" examines scientific developments in gene therapy, culminating in the ability to make precise edits to DNA, even that of human beings. The discovery of something called CRISPR-Cas9 editing has shown early promise for holding a cure for several debilitating or even deadly genetic diseases, but it also has the capability of modifying healthy genes. The implications of the latter raise ethical questions as to whether scientists should be altering human DNA at all.