A man and a woman walk into a doctor’s office. She has a cat allergy; he has a cat. “They say, ‘You’ve got to do something or we can’t get married,’” says Michael Blaiss. It sounds like the beginning of a bad joke, but it’s actually a typical day at Blaiss’s private allergy practice in Memphis, Tennessee. People often face tough decisions when a loved one cannot cohabit with feline companions.