Gypsy Rose Blanchard's Waiting to Establish Paternity, Ken & Ryan Can Wait

The confusion surrounding the paternity of Gypsy Rose Blanchard's unborn baby won't be cleared up any time soon ... TMZ has learned her ex, Ryan Anderson, has decided to wait on taking a DNA test.

Sources close to Ryan tell us ... Ryan and Gypsy plan to delay DNA testing until after her baby girl is born ... since it's easier and cheaper to wait.

We're told the paternity test before the baby is born can cost anywhere between $500 to $2,000 -- whereas a post-birth test is in the $150 to $200 range.

Gypsy Rose previously claimed her fiancé, Ken Urker, is the baby daddy ... but fans think her pregnancy timeline is a little iffy.

But, according to Louisiana law, if Gypsy Rose gives birth BEFORE their divorce is final, Ryan would be listed as the father on the birth certificate ... and the only way to change that would be with a paternity test showing Ken's the dad.

Kim Kardashian dealt with a similar headache when she got pregnant with her and Kanye West's first child, North West -- while the reality TV star was separated (but still legally married) to NBA star Kris Humphries. Kim and Kris finalized their divorce mere weeks before Northie was born, so there was a clear path to list Ye as the papa.