Let's clear up this. Nick Savage, who is FBI, is a friend of Lennie's. Lennie who loves to spout his stories by degrees of separation, convinced Nick somehow, don't ask, that Lee was Caylee's father. In the mean time, Lennie was spouting this to NG, who took off running with it and the media also did. This rumor had a life of it's own. We here discussed it.
Savage ordered this test to put an end to it, one way or another. Once the DNA analysis was reviewed by WS members, GA was also ruled out. Note, it was AZ who was one of the first to explain it as has joypath. The official explanation is all in a supplement report released by LE in the docs we have in the reference thread.