▁the ▁new ▁methods ▁of ▁induced ▁pl ur ip ot ent ▁stem ▁cells . ▁Though ▁recent ▁studies ▁have ▁put ▁in ▁question ▁how ▁similar ▁i PS ▁cells ▁are ▁to ▁emb ry onic ▁stem ▁cells . ▁Ep igen etic ▁memory ▁in ▁i PS ▁affect s ▁the ▁cell ▁line age ▁it ▁can ▁differenti ate ▁into . ▁For ▁instance , ▁an ▁i PS ▁cell ▁derived ▁from ▁a ▁blood ▁cell ▁will ▁be ▁more ▁efficient ▁at ▁differenti ating ▁into ▁blood ▁cells , ▁while ▁it ▁will ▁be ▁less ▁efficient ▁at ▁creating ▁a ▁neur on . ▁This ▁ra ises ▁the ▁question ▁of ▁how ▁well ▁i PS ▁cells ▁can ▁m im ic ▁the ▁gold ▁standard ▁E SC ▁in ▁experiments , ▁as ▁stem ▁cells ▁are ▁defined ▁as ▁having ▁the ▁ability ▁to ▁differenti ate ▁into ▁any ▁cell ▁type . ▁SC NT ▁stem ▁cells ▁do ▁not ▁pose ▁such ▁a ▁problem ▁and ▁continue ▁to ▁remain ▁relevant ▁in ▁stem ▁cell ▁studies . ▁ ▁Re product ive ▁cl oning ▁ ▁This ▁technique ▁is ▁currently ▁the ▁basis ▁for ▁cl oning ▁animals ▁( such ▁as ▁the ▁famous ▁Dol ly ▁the ▁sheep ), ▁and ▁has ▁been ▁theoret ically ▁proposed ▁as ▁a ▁possible ▁way ▁to ▁clone ▁humans . ▁Using ▁SC NT ▁in ▁re product ive ▁cl oning ▁has ▁proven ▁difficult ▁with ▁limited ▁success . ▁High ▁f etal ▁and ▁ne on atal ▁death ▁make ▁the ▁process ▁very ▁in efficient . ▁Result ing ▁cl oned ▁off spring ▁are ▁also ▁pl ag ued ▁with ▁development ▁and ▁im print ing ▁dis orders ▁in ▁non - human ▁species . ▁For ▁these ▁reasons , ▁along ▁with ▁moral ▁and ▁eth