Darwin barely mentioned the whole human species in his Origin of Species but it still inspired his cousin Francis Galton to develop Eugenics[1]: Whether you selectively bread humans to improve the species or dumb it down, who's to tell the difference? Darwin himself had less luck with his person contribution to the evolution of the species, his youngest being described as "backward in walking & talking, but intelligent and observant", which was surely due to him having married his cousin: "We are a wretched family & ought to be exterminated."[2]

The problem of a) people ruining their health and b) not having enough donor organs can be solved much easier by encouraging active transport over the personal 2t metal box, reducing sugar, salt and others in our processed foods and of course legislation to make organ donations possible even without the deceased having agreed before. The opt-out in countries like Austria and Spain raises the level of awareness but of course still needs excellent communication.

[1] https://rss.onlinelibrary.wiley.com/doi/full/10.1111/j.1740-... [2] https://www.theguardian.com/science/2009/jan/19/charles-darw...