Here's why:
* Different species: Pitbulls are dogs (Canis lupus familiaris) and deer are mammals belonging to the family Cervidae. They are different species and cannot interbreed.
* Reproductive incompatibility: Animals from different species have incompatible reproductive systems. Their chromosomes, hormones, and mating behaviors are not compatible, preventing fertilization.
It's important to remember that interspecies breeding is scientifically impossible, and any claims suggesting otherwise are incorrect.