She said she had always intended to tell them as early as 3 years old but she kept putting it off and putting it off and now she felt like she had to tell them but she was afraid they were going to get really upset or ask a lot of questions about the donor that she couldn't answer or look at her "like I'm not really their mother."
She had books to read to them and had even rehearsed what she was going to say but she was still scared to death.
I assured her that it was highly unlikely that her kids would get upset by this information (especially if she presented it in an upbeat way). I also told her that although they might ask who their donor was, they were also very unlikely to ask many more detailed questions at this age.
She could answer the "who is my donor" question by saying "We never met her but we know she must have been a very nice person who wanted to help us." (Only when they are older would she need to get into more details and share whatever information they had).
By the time we finished talking she was "still stressed" but just "wanting to get it over with." I hoped she'd follow through. She was feeling so guilty about not telling with each passing day, and the longer she waited the bigger it felt.
A few days later we talked again. She was overjoyed to report that she read the book to them and talked to her kids about their own donor story. Both twins listened and her daughter asked "Does everyone have a donor?" "Not everybody," she answered, "But alot of people do." "Oh," her daughter she said. "What are we having for lunch?"