To the waters and the wild
With a faery, hand in hand,
For the world's more full of weeping
Than you can understand.
The feather light touch of the fey can be seen in most human cultures, from simple superstitions about hanging cold iron above the doorway to the practice of tithing bread and milk to the local fey-lords so they will leave the harvest in peace.
The feyborn are the product of mortal parents whose blood contains some tinge of fey magic. Many are born to human parents, although their ancestry may be tinged by a great-grandfather cavorting with a dryad, but some are the result of a powerful blessing from a fey creature of great power while the child is still in the womb. The favor of a fairy is a powerful thing, and their good will towards one who is not yet born can have a powerful effect on their blood and destiny.
Racial Ecologies is line of small supplements from Fat Goblin Games. Each one is richly detailed with information on racial histories, personality, physiology, and all the details on playing the race, including optional racial traits, character traits, feats, new equipment, and a full stats on an NPC you can use in your next game.