gn, gen. This root is so prolific that some scholars divide it in two. It defies partition. For its two meanings, to know and to beget, continue to entwine through the linguistic changes...Shakespeare, in As You Like It, iii, 2, has Rosalind say, "As the coney [rabbit] that you see dwell where it is kindled." To kindle a fire is to beget the flame; from Latin form of this root we have ignite. We retain the word kin, and have adopted kindergarten and Kriss Kringle, little Christ Child.
A punning rhyme is made in the Massinger-Dekker play The Virgin Martyr (1622): "A pox on your Christian cocatrices! They cry, like poulterers' wives, No money, no coney." In fact, the rabbit may have gotten its earlier name, coney, from its prolific nature. Since the word coney appears in the Bible, a pious euphemistic note advises: "It is familiarly pronounced cunny, but coney is proper for solemn reading." Perhaps a similar primness gave the long vowel to Coney Island, New York, named for the rabbits the early Americans hunted there. From the "knowing" sense came the word cunning; but from the "begat" sense came cunny (alpha and omega, the beginning and the end of the begetting), cunt, cunnilingus.
--From Joseph T. Shipley's, The Origins of English Words: A Discursive Dictionary of Indo-European Roots