I have a weak villager, but every time I try to have someone heal him, they just try to mate with him instead. This is even if "Healing" is checked in their skill preferences. One of my villagers is a master doctor and even he tries to just have sex with the patient. Don't any of the healers in this game has a sense of professionalism? You don't hit on patients!

How can I differentiate between healing and mating when I drop a villager onto him?