I am not sure of your context. Do you mean his physical child with Mary Magdalene, or are you speaking metaphorically?
I think somewhere the Bible says that we are his brothers and sisters, and that would mean we are the children of God. I do not believe everything we are told about Jesus because it is mostly hearsay. The four gospels were written years after his death, and they had to depend on oral history. However, I believe that we are all made as part of God's spirit and body (made in the image of God) and therefore we are his brothers and sisters just as he said we were.
In the physical context, if I found out that I was his child, right now I would be very old. LOL However historians are going to great lengths to try to prove that the Merovingians descended from a physical child of Jesus and Mary Magdalene. If I found out that I was of Merovingian descent, I would be thrilled, but it wouldn't change my life because it wouldn't mean anything to anyone else and wouldn't be of any influence.