odd male feline behavior?

Question
I have 2 cats; a male and a female, both turning one year old this month.  
They are both going through some personality changes.  Her becoming more
friendly,  And he becoming more passive-aggressive.  I understand that this
is him trying to assert his dominance.  He was a very affectionate, cuddly,
kitten, but now he can't seem to make up his mind wanting to be pet, and
pushing away.  A bizarre behavior that I have noticed is that while being pet,
he moves his body as if he wants his genital regions pet.  Is this a concerning
behavior of an internal problem?  I have not noticed any unusual stools or
squatting.  Or is this behavior part of a natural progression of growing up?

Answer
Jen,

Have you gotten both cat spayed and neutered? If not that would explain part of the behavior changes.

At one year old they are 15 years old in human years. Cats also go through a kitty form of the teenage years and growing up. They are caught between being a kitten and being a cat.

Your cat may like his back scratched by the base of the tail. Some cats love to be petted there. That is also the area that fleas bite so scratching there feels good to some cats. No, it isn't a sign of an internal problem.

Tabbi