William Luddington and Martha Rose were step-siblings.
"William (Luddington) … m (1) Martha [da. John Rose]."
"Martha3 (John2, Robert1)) … m. ca. 1678, William Luddington, Jr., her step-brother of New Haven, … son of William Sr. and Ellen (Moulthrop) [(Nicholl); see TAG 74:95-96 and 215-16] Luddington."