This leads to him getting pregnant with himself.
Now I wonder, is this even possible? Say, as a male, produce some sperm, then by some means completely change to female(complete with working reproductive organs), then inseminates themself, is it biologically possible to produce offspring? Would said offspring be essentially a clone of the parent?
It is possible, in fact there are scientists working on it (in principle, you take the DNA out of a sperm and put it in an empty egg cell, then fertilize that egg with another sperm.). The child will not be a clone, in fact there is a 25% chance of a man's DNA recombining to produce a daughter, if both sperm carry his X chromosome (although a woman cannot produce a male child this way, since she has no Y chromosome). The child also has a high chance of manifesting any recessive traits of the truly single father, like blue eyes or Tay-Sachs disease.
That's also a 25% chance of 2 Y chromosomes and that dosent end well. Even if you can make a baby that way its basicaly double incest.
so.. yea.
Due to the way human chromossomes are distributed among sexes, a YY human being is impossible under any other circunstance than what has been suggested here. So it would make an interesting subject to study, at the very least.
If this is anything to go by, XYY humans do not show any significant difference in behavior in comparison to normal humans, they just tend to grow faster and a little bigger. XXX and XXY ones are much worse off, being severely mentally handicapped in comparison to the average XX or XY human.
That is, assuming that one can even create life using only Y chromossomes. All we know is that the X chromossome seems necessary for (human) life as we know it. A YY combination might not even generate anything.