A disproportionate majority of child molesters are heterosexual. Even with all the societal support marriage receives, the divorce rate is spiraling. There seem to be very few happy heterosexuals. Techniques have been developed to help you change if you really want to. Agreed, we are not prepared for this one, but it has to be carried off perfectly.
Automatic weapons are undeniably the best deterrent to missionaries.
For extra effect, fire a few rounds into the air or towards their car. Pretend you hear a voice inside your head telling you to kill the missionary. Guaranteed to stop future visits for several years. The young couple came to my door. I was wearing my robe, and had just awakened.