Answer:
The word "bitch" refers to a female dog, and is not an inappropriate word in that context. In terms of insulting human beings, the word "bastard" is often used for men, although the word does not have an equivalent meaning to "bitch". "Bastard" means "a son born outside of marriage".
When talking about dogs, the female is a bitch, and the male is just a "dog". In breeding terms, the father of a puppy may be called a "sire". A male dog used for breeding is a "stud" (this is a common term for any male animal used for breeding).