Should I wait for my female dog or cat to have at least one litter before spaying?

Definitely not.  Cats and dogs can be spayed from as young as 8 weeks and should be spayed before they are six months of age. There is no benefit in allowing the animal to have a litter before spaying, and in fact by doing so you are adding to the over-population problem.

On the other hand, spaying dramatically reduces your female’s risk of developing uterine infections, ovarian cancer and breast cancer.  In fact, it was found that female dogs that are spayed before their first birthday are 99.9 percent less likely to develop reproductive cancer.

The males benefit as well as neutered males have far fewer prostate problems (including cysts, abscesses, and prostate cancer) than do unaltered males, and they can’t develop testicular cancer. They are less likely to roam, fight, demonstrate aggressiveness, or display hyperactive behavior.