Goddard was interested in the heritability of "feeble-mindedness"—and often wrote of the invisible threat of recessive "feeble-minded" genes carried by otherwise healthy and intelligent looking members of the population (Mendel's laws had only been rediscovered a decade before; Goddard's genetic shorthand was, in its day, considered to be on par with cutting-edge science). It was in tracing the family history of Deborah that Goddard and his assistants discovered that Deborah's family of drunks and criminals was related—through Martin Kallikak—to another family tree of economy and prosperity. On the "normal" side of the Kallikak family tree, the children Martin had with his wife and their descendants all ended up prosperous, intelligent, and morally upstanding. They were lawyers, ministers, and doctors. None were "feeble-minded". Goddard concluded from this that intelligence, sanity, and morality were hereditary, and every effort should be undertaken to keep the 'feeble-minded' from procreating, with the overall goal of potentially ending 'feeble-mindedness' and its accompanying traits. The damage from even one dalliance between a young man and a "feeble-minded" woman could create generations and generations worth of crime and poverty, with its members eventually living off the generosity of the state (and consequently taxpayers), Goddard argued. His work contains intricately constructed family trees, showing near-perfect Mendelian ratios in the inheritance of negative and positive traits. Goddard recommended segregating them in institutions, where they would be taught how to work various forms of menial labor. Present-day evaluation In its day, The Kallikak Family was a tremendous success and went through multiple printings. It helped propel Goddard to the status of one of the nation's top experts in using psychology in policy, and along with the work of Charles B. Davenport and Madison Grant is considered one of the canonical works of early 20th-century American eugenics. Research published in 2001 by David MacDonald and Nancy McAdams revealed that Goddard's account of the division of the Kallikak family into a "good" lineage—descended from Martin Kallikak Sr. and his wife—and a "bad" lineage—descended from Martin Kallikak Sr. and an unnamed feeble-minded barmaid—was fictitious. Martin Kallikak Jr., the supposedly illegitimate offspring of Martin Kallikak Sr. and the barmaid, was in fact the son of Gabriel Wolverton and his wife Catherine Murray. His real name was John Wolverton (1776–1861), and he was a landowner prosperous enough to buy two tracts of land for cash in 1809. Census records of 1850 show that all the adults