Man, 48, who has the ‘mental ability of a nine-year-old’ is jailed for incest after having a child with his estranged daughter A 48-year-old man has been sentenced to four years in prison for incest after having a child with his estranged biological daughter. Gympie District Court heard the pair reconnected almost two years before they struck up a sexual relationship from 2008, The Gympie Times reported.