I do a double-take every time I see this ad1 at Logan Airport:
While the poster is actually encouraging owners to spay and neuter their pets, I always think it might be a “safe sex” ad. Something more like this:
The business of this would really make more sense. After all, spaying and neutering are a one-and-done procedures. But with kitty condoms and doggie birth control pills, veterinarians could be making money year after year.