Will a puppy grow up normal(big/strong/muscle) if its been castrated young.?

What i mean is hormones like testoterone that turn a boy to a man are in his balls, so no balls, no hormone no growth? Is it better to wait till the dog is grownup?.

Better to do it now. It won't affect his growth at all.

There is a rumor that says your dogs growth will be stunted if they get neutered too young, but I highly doubt it is true.My German Shepherd was neutered at 3 months and he is 102lbsIt really prevents your dog from marking territory (lifting leg and peeing all the time), roaming(running away from home), breeding and diseases.

Actually, they still produce a very low level of testosterone and testosterone affects bone grown rather than muscle and strength. Neutering a very young puppy can have an effect on growth plates, which doesn't make them smaller but actually longer boned. The idea to wait till a puppy is closer to year is not because the dog will be more masculine but that injuries don't incur from joint weakness due to the growth plates possibly deforming from decreased levels of testosterone. It's unlikely that you'd notice or ever have any issue from neutering earlier. In fact, many vets are neutering early just because of the over population issue. If I were you I'd contact your vet, a major small animal surgery clinic or university and ask them their views on the subject.