While I'm definitely pro-desexing, and definitely like it to be done at 6 months for pet dogs that are at risk of breeding (obviously not breeding dogs), there's actually quite a bit of literature that shows that 6 months is not always the ideal time to desex. A study in 1991 found that a number of factors including the sex hormones are what promote the closing of the growth plates in dogs. So it's actually the opposite of what is believed; dogs desexed early are actually more likely to be bigger than late-desexed or non-desexed dogs because the growth plates take longer to close and their bones continue to grow for longer. This can cause a higher incidence of things like hip displasia and damaged cruciate ligaments later down the track. This obviously makes it a difficult choice for some owners as to when they should desex their dog as they have to balance the risk of changing their dog's natural growth with the risk of sex hormone based behaviours. A 2004 study actually found that early desexing can increase the incidence of sexual behaviors in males and females...

While that seems a little off-topic, I just wanted to put it out there in case anyone was thinking that the OP was negligent in not desexing yet.
Yup, thats what several of the vets at our local practice told us. The growth plate thing is more for big dogs that take longer to grow to full size, whereas the sexual behaviour part is more apparent in little dogs but not limited to little dogs. We got our Silky Terrier desexed bang on 6 months and now at 11 years of age he STILL humps anything and everything in sight!

I was thinking as well that, Reet, if the day comes that you do have to make the decision to get rid of Yogi, don't automatically go to destruction - there are other options. Rehoming as a pet for a Pitty probably isn't the ideal, but the police force, military, and private security companies don't just take German Shepherds you know! If he does show some concerning aggression but isn't completely vicious, he could make the perfect security patrol dog, and in the hands of a qualified and experienced trainer he could have the best of both worlds.

Like I said in my previous post, I would only be really trusting the advice of your vet on this matter. I think I read you've got Yogi booked in for his big op next week? I'd be bringing it up with the vet then, and see what the expert has to offer.