General terms:
* Intact male: This simply means he hasn't been neutered. He may be unable to have babies due to other reasons (health issues, congenital defects, etc.).
* Infertile male: This describes a male who is unable to father offspring, regardless of the cause.
More specific terms:
* Neutered male: This is the most common and accurate term if the dog has been surgically sterilized.
* Cryptorchid: This refers to a male dog with one or both testicles not descended into the scrotum. This condition typically makes the dog infertile.
* Sterile male: This can be used if the dog is infertile due to medical or genetic reasons.
The best word to use depends on the specific context and the reason for the dog's inability to have babies.