I disagree that biology or medicine can predict what will happen to an individual. The problem lies in the fact that people, or biological systems in general, are not a uniform media. You can predict odds based on a population meeting X, Y, and Z criteria, but that's the limit of the science. The anatomy/chemistry/psychology of a single person is unique to that person, and a sample size of 1 is near useless without a complete understanding of the mechanisms (which we don't have).

The problem of variability also extends into pure hard sciences like metallurgy. A certain material, with a certain composition, unit cell structure, grain size and orientation, heat treat, forming process, etc. will still have variability in its properties. You can see the differences in A-basis (99% values with 95% confidence are greater then stated value), B-basis (90% values with 95% confidence are greater then stated value), and S-basis (industry specific) strengths for a particular material.