It is probable that Chaucer and Philippa had "two sons and two daughters", whose birthdates are unknown. A lurid conspiracy theory was put forth, first by Mary Eliza Haweis in the late nineteenth-century, and then again more influentially by Russell Kraus in 1932, that "one or two" of these children had been illicitly fathered by John of Gaunt. Many scholars, including almost all contemporary Chaucerians have argued against this theory; H.A. Kelly, for example, has effectively demonstrated that this belief is likely false as John of Gaunt having sexual relations with two sisters would have been considered incest and would have required additional papal dispensation for him to marry Katherine. Samantha Katz Seal argues that literary critics deliberately encouraged the idea of a "harlot" Philippa for the same reason that earlier critics had believed in a "shrewish" Philippa, namely that alienating Chaucer from his wife and domestic circles allowed these critics to imagine a more masculine Chaucer, and to claim that they, his critics, understood Chaucer better than anyone else ever had, especially his wife.