Pine Nut

The seed of the pine tree, found within pinecones, is called a pine nut, or pignoli. It's easily found in grocery stores, either on their own or as part of pesto. There are at least three main groupings of pine nuts, each with a slightly different taste, but in general they are delicately flavored and pleasantly textured.
In the second century A.D., the Greek doctor Galen prescribed pine nuts to his patients who had problems producing children. It's unclear whether the goal was better fertility or simply an increase in the number of attempts, but his recommendation has survived for nearly two millenia and is echoed by cultures worldwide. Current thinking leans toward their increasing the libido, but I've yet to find any reliable evidence to corroborate it.