My suspicion is that while there may be statistically relevant differences on average at the population level, boy and girl cat behavior overlap so much that it's more an issue of individual cat than of cat sex.
This is one of the many reasons for why I love cats so much. Each one truly is so unique and different to all the rest, just like people (and of course many are also similar in other ways), so it's always so neat to see the differences from cat to cat.
