I would say 6 months old defiantly. I'm not saying all breeds or all dogs.
However I have seen "accidents" (although I feel far too many can be prevented).
A 6 month old male got a 8 month old female pg. A 9 month old male got his mom pg. An 8 month old got his sister pg (we thought they wouldn't mate since they were brother & sister is what they said). Someone else told me that too, when I told them they should not have the brother/sister who were 7 months old at the time in the same kennel. They said we thought they wouldn't breed? I'm like yeah they will for sure. I also seen a 7 month old male at stud who had already sired 2 litters and was a "proven producer" sickening!! One other I seen was a bit older, 9 months that got his mom pg.
Okay... sorry. I meant virility! When is a male pup viril? I think everyone knew what I meant though. I didn't want to say 'When is a male mature enough to breed?' b/c then everyone would misinterpret my question.
"There is an easy simple way to guesstimate if you should worry about a male.
If he lifts his leg while peeing, odds are he is ready and able to do the deed. Since the hormones that trigger this behavior are the same ones that trigger sperm production, it is a pretty good indicator." =========================================================== Juno, I hope your wrong about that. Our Toy Poodle pup Trey Kool was able to lift his leg at 9 weeks. I agree that it probably depends on the breed and the dog. I believe that toy breeds mature physically earlier than large breeds. Toy Poodles are physically mature (finished growing) between 6-12 months where as our Standard Poodles were not done growing til' almost 2 yrs. of age.