Board Thread:Naruto Discussions/@comment-34700383-20180829185752/@comment-33485854-20180906041156

LegionZero wrote: @littlegen: Magnet release can be used to magnetize objects that arent normally magnetized. One of the novels addresses Gaara as a Magnet release user. Some ppl take the novels as canon and others dont. Its really up to what you want to believe on that one.

I think it more plausible he inherited from Shukaku, considering Temari and Kankuro don't have the Kekkei Genkai.