You can't breed dogs in The Sims 2. The game doesn't have any mechanics for breeding pets.
While you can have male and female dogs in your household, they won't interact in a way that leads to puppies.
If you're looking for a Sims game where you can breed dogs, you'll want to look into The Sims 3 or The Sims 4. These games both allow you to breed pets, including dogs.