Male and Female Dogs: Physical Differences
Physical Traits and Appearance

Experienced dog owners can distinguish between a male or female dog simply by looking at them. Female dogs tend to be a bit smaller than males which can be advantageous if you live in a smaller apartment and are looking for an appropriate pet.
Such a difference in size might not hold at all times, but a male puppy from a purebred litter generally grows slightly taller and heavier than females of the same age. The size difference is also less noticeable if the male dog is neutered at an early age which will slow its growth.

Male dogs tend to have a larger head and a more masculine look, while female dogs tend to have softer features. These differences in appearance, while noticeable for many people, might not be very relevant.
Appearance only affects preference in terms of how you want your dog to look, but the dog’s sex becomes more meaningful when we consider biological differences and hormonal differences.
Reproductive Health
Spaying and neutering dogs is standard practice amongst owners. It prevents the dogs from reproducing, halts the development of sex-associated behaviors, and reduces stray dog populations. Female dogs are spayed through a procedure called an ovariohysterectomy, through which the vet removes the dog’s ovaries and other reproductive organs.
Male counterparts are neutered by removing their testicles through a process called an orchiectomy. Spaying female dogs and neutering male dogs make it easier for owners to maintain them, especially when they reach sexual maturity or are in heat.
Female dogs are in heat around two times per year for two or three weeks each time. This experience is called estrus, meaning that the female dog can reproduce and carry a litter.
Her body produces pheromones or a type of vaginal discharge or bloody discharge that attracts male dogs. If the female dog is allowed to be close to non-neutered males, she will get pregnant and carry a litter.
Male dogs, on the other hand, are more likely to display signs of aggressiveness if they are around females in heat. Different from female dogs, male dogs tend to display sexual activity all year long.
Once a male puppy reaches sexual maturity, if not properly trained, it might start marking the house or new places. A male dog is also more likely to mount people, soft objects like dog beds and pillows, and other dogs which could lead to dangerous altercations.
While spaying/neutering your dog could curb some unwanted behaviors early, it’s not automatically true that these issues will stop coming up entirely. However, what spaying and neutering does 100% prevent against is unwanted litters.
In other words, training is the best way to prevent and stop these behaviors. Additionally, it’s important to consider that, sometimes, spaying or neutering pups too early cuts off important hormones which can interfere with natural and healthy development to full maturity.
Spaying and Neutering: Effect on Health Conditions
Spaying and neutering can have a great impact on the entire dog population, as taking this important step will prevent unwanted breedings and new litters. Spayed females are less likely to have health issues like uterine infections or mammary cancer. And, neutered male dogs are more likely to avoid testicular cancer and benign prostatic hyperplasia.
To get these benefits from spaying and neutering, you should carefully plan the timing of these procedures. In the past, most vets recommended spaying and neutering early. As a result, many dogs had a tendency to develop health problems, including different types of cancer or orthopedic issues.
Nowadays, the consensus is to wait until the dog is physically mature. So while both procedures are beneficial to the dogs, they expose health differences between male and female dogs that spaying and neutering help minimize.