I take it you're not considering Veterinary Medicine as a health profession but that was what I thought I wanted to do for a long time. I chose Medicine for several reasons, but just in terms of comparing the professions, working in Veterinary Medicine can be very disheartening. The law offers very little protection for animals. When a pediatrician suspects that a patient is being abused or neglected, he or she is legally required to report it, and a social worker comes in to evaluate the child and talk to the parents. When veterinarians see signs of abuse or neglect, they usually keep quiet because they know that the courts will do nothing and they will lose this client and many others. As a consequence, you spend a lot of time taking care of animals that have been obviously mistreated, and when you send them home you know that it's not going to get any better and there's nothing you can do about it. Also, veterinary medicine is controlled much more by economics. As a person, if you go to an ER, the staff is required to treat you, whether or not you can pay for it. If parents cannot afford simple, necessary treatment for a child, there is always a way for the child to be treated. However, if you can't pay or don't want to pay $100 for IV's to rehydrate your sick puppy, you can always pay the vet $15 to euthanize him instead. Finally, there's so much you can't do for your patients if you're a vet. The technology is moving forward, but it's not available or practical for the majority of pet owners. So many pet owners are forced to give up on their pets because of conditions that would be treatable in humans.
I realize that human medicine has its limitations, but they are not as restrictive as those of veterinary medicine. People generally want to live and be healthy, and in this respect physicians work with their patients rather than against them.