Take the Nag Hammadi scrolls for example. I don't think anyone doubts their authenticity and yet we still seem to manage to almost completely ignore their content. Are you aware that from them we have:
- There is a Gospel of Mary (yes that is Mary Magdalene)
- after Jesus died there was a fight for control of the emerging church, which of course Peter won. But did you know the person he struggled against and who hearly took control was again Mary Magdalene.
- There was a gospel of Peter, which the Catholic church rejected (despite the fact that he was the first leader of the church). Why? Because Peter stated in his writings that Jesus was not God made man but was god and therefore did not actually
suffer on the cross which contradicted the churches chosen philosophy of salvation through suffering (very necessary to get themselves through those early years of persecution).
- There are many others such as Thomas's gospel which reads like a zen buddhist script.
Now I'm not saying what the rights and wrongs of this are; the interpretations of the dead sea scrolls are many and varied (particularly in the area of whether Mary Magdalene was Jesus' lover/partner/wife) and I am no expert theologian (or even an inexpert one for that matter). However most of my comments above are fact and not interpretation and my real point is that even if the books contain controversial information about Jesus it can and will be interpreted differently to suit different people whether for or against religion.
Incidentally if you are interested in translations of the gospel fragments from the Nag Hammadi scrolls then you can access them for free here:
Gnostic Society Library: Sources on Gnosticism and Gnosis