Perhaps our greatest distinction as a species is our capacity, unique among animals, to make… — Jared Diamond

Though seemingly remote from human sexuality, shorebird sexuality is instructive because it illustrates the main message of this book: a species’ sexuality is molded by other aspects of the species’ biology. It’s easier for us to acknowledge this conclusion about shorebirds, to which we don’t apply moral standards, than about ourselves.

Behavior evolves through natural selection, just as anatomy does. Hence if sex is enjoyable, natural selection must have been responsible for that outcome.

Our sex is ultimately laid down by our genes.