Example: Arthur Tudor dies, leaving the throne of England to Henry VII
Conceivable (pun not intended) Arthur may have had more Y chromosomes than Henry, staying married to a son-bearing Catherine of Aragon. Protestantism would have come to Britain in some form or another no matter what, but not as abrupt a split as under Henry VIII - more like France under Henry IV of France: some blood but eventually only nominally Catholic.
Or Tsarevitch Nicholas of Russia dying, leaving the throne open to Alexander III. Nicholas was the smarter of the two; enough that he might have continued reforms even after his father was assassinated. A smart brain would see that Alexander II had been killed not because he was too autocratic, but because his conciliations prevented the revolution his assigns wanted. But Alexander II came in with a stupid iron fist.
Scenario 1: Heir was replaced by better spare:
Example: Edward VIII bailed out; George VI did a stand-up job.
Scenario 3: if only the heir had been replaced by the better spare
I don’t have an example of this off the top of my head.
It’s presently a “probably,” but a lot of people are lukewarm at best about Charles, the Prince of Wales, becoming King. Aside from his family life foibles (and in fairness he is by all accounts a good father) he can come across as a bit of a flake - one whose heart is often in the right place but whose judgement isn’t as solid as his mother’s.
I think a lot of folks could be convinced Andrew might do a better job.
Edward II - the guy who in “Braveheart” was portrayed as an outright prancing queen, amongst other historical doubts and inaccuracies - was a lot different from the guy in the movie but was a pretty awful King. His younger half brother Thomas might have been a better choice, although Thomas had his own problems.
Really, though, Edward VIII/George VI is the hole in one right there. Shit, their own family would muse, long before the Simpson fiasco, that they wished Albert/George VI had been born first. Everyone knew Edward VIII was a doofus.
Splutter! Randy Andy? You must be kidding! OTOH this is Charles we’re discussing, so it is debatable. Now if you had said Anne… But I think most would rather the Throne went straight to William.
George V was also a younger son, his elder brother was the ‘colourful’ Prince Albert Victor. Another case of scenario 2 (spare succeeding who is better than the heir) perhaps?
Henry certainly wasn’t short of Y chromosomes; he had lots of sons, it’s just that most of the legitimate ones were stillborn or died in infancy. There’s no particular reason to think Arthur would have been any better at fathering male offspring (although I guess he probably wouldn’t have reacted by marrying one wife after another after another after another after another after another, because, well, most people don’t).
The Windsor dynasty is unusual in how many monarchs in it were “spares”. Only two, Edward VII and Edward VIII, were heirs apparent from birth. Victoria and Elizabeth II were daughters who became Queen only after no male heirs arrived. And George V and George VI were younger sons who replaced a brother.
Ferdinand of Aragon was a spare to Aragon; he shouldn’t have been king of Navarre at all. His elder step-brother, Carlos, first Prince of Viana (the title still held nowadays by the Heir to Navarre), was heir apparent to Aragon and uncrowned king of Navarre, but their father John II of Aragon wasn’t willing to accept that he was not himself King of Navarre (repeat after me: “consorts do not inherit their spouse’s domains”), or to let Carlos (who was on the geeky side) rule.
If you ask the Jews, Muslims or Navarrese, Ferdinand was a sonofabitch; in Navarre we still use the name of the town where he was born as a curse. If you ask Machiavelo or Stalin (who used many techniques Ferdinand had used, although the Aragonese would often hide the poison somewhat and Stalin was as subtle as an avalanche), he was the god of Politics.
Most people are not hereditary monarchs under a system where female monarchs are discouraged. Most people who were in that situation didn’t have the same trouble getting surviving sons that Henry VIII did, or had other male relatives that made it less imperative that they have a son.
Henry VIII and Catherine of Aragon did have a son, who died at the age of 53 days. If he had survived, English history would have been rather different, regardless of what he ended up being like as a ruler.
Even if Arthur was XYY, that wouldn’t have made him more fertile. We can be pretty sure Henry VIII did have a Y chromosome. XO (one X chromosome, no Y) children are female with Turner syndrome, not male. XX males do happen, but are always sterile.
And it normally would have been a simple matter for a man in Henry VIII’s position to get a [del]divorce[/del] annulment from Rome, but unfortunatly for him he his wife’s nephew was basically holding the Pope hostage.
They had three sons. And three daughters. All of whom died at a very early age except for Mary, who would eventually become queen.
Henry also had two sons (both of whom died early) and a daughter (the future Queen Elizabeth) with his second wife Anne Boleyn and a son (the future King Edward) with his third wife Jane Seymour. And he had at least at least one and probably three illegitimate children, two sons and a daughter.
So whatever Henry’s other problems might have been, he wasn’t shooting blanks. Nor did he have a problem fathering male children.