I can see some of the early impacts from Henry having a healthy son at that point. First, he probably would have been more motivated to keep Anne Boleyn around, thus eliminating OTL's Edward. Second, this new King (I would guess he'd also have ended up as Edward VI, but I'm not 100% sure, would have succeeded to the throne in 1547 and probably enjoyed a long reign.
But from there things get very difficult for me to even guess at. The Catholic's would probably have still seen Mary as the legitimate heir since they never approved of Henry's divorce. This would make the Catholic/Protestant issues both internally and internationally still an issue for this King Edward, but there would be a strong male ruler, and an earlier one, to deal with some of them.
Given the pivotal nature that the late Tudor reign has on world history -- it also being the start of the "Age of Exploration" and colonization, a major period in the European doctrinal wars, etc. -- I could easily imagine that the resulting world would, by 2009, be almost unrecognizable to someone from OTL.
But I could be completely wrong, even from my first assumption that this Edward wouldn't have health problems.
I also will not claim that this isn't a very common point of departure for alternate history fiction.
Any comments?
