How can you tell a male dog from a female dog?

First, an adult male of the same breed is usually larger with more solid muscles. Second, observe the genitals and anus: the male’s genitals are round, the female’s are linear or teardrop-shaped, and after maturity the male develops two oval testicles while the female does not. The male’s genital opening is farther from the anus, while the female’s is closer. Finally, male dogs usually lift a hind leg to urinate, whereas females squat..