Honesty is the best policy. Let your child know they were an accident, the magnitude of the accident well that is up the parent to decide. Pull your child in to a room that is set up like a job interview, and tell them that the good news is they were not adopted, but emphasize the fact that if they were adopted, well we probably wouldn’t have picked you, especially if we had a choice, tell them to thank their lucky stars you didn’t leave them on the Fire Departments porch and run away. Then slightly turn your head away from them and say you can’t even look at them right now, explain how they were a major accident and every time Mommy cries it is because she is thinking of you and how you ruined her life. This tip doesn’t really correlate to an effective child-rearing tip and really there is no lesson to be learned here, it is just funny to watch your children cry.