I should add that so far Merlin has only met one child, at the vet's. She was a girl about 10-11 years old who asked to pet her. She was calm, and confident and I didn't expect Merlin to dislike her, but Merlin was terrified more than I've ever seen her. She ran up to my shoulder and started trembling before the girl even reached out. Then as we were leaving a family came in and she was again scared by the presence of kids. So she may have had a bad experience. My friends' children are grown up or teens now so she may not get much exposure to them anymore. I do have a 6 year old niece, but my sister expects everyone to travel to her rather than the other way around, so I don't know when they may visit again. Last time they were here, she was about 2 and my conures liked her fine.
One friend has a son who was quite hyper as a young child. One day when they were here, we went into the kitchen to get lunch and then realized he wasn't with us. She said, "Oh no! He's with those birds!" and we rushed back into the front room. Well, he was in front of Rowdy jumping up and down and yelling and she was doing the same and chirping happily. After that we knew Rowdy was fine with a young boy who, well, acted a lot like her! They did this often over the years, but now that boy is in high school and doesn't really act like that anymore. Rowdy probably would have enjoyed it if I had had children of my own; we just would have had to watch the toddler stage carefully.