Haley funny/sad

Yesterday she was watching ER with me and there was a guy who had a younger brother. All of a sudden she looks at me and says "I want a baby brother" I kinda giggled and said "You do" she says "yes" so I tell her to ask her dad. I call Kirk and she gets all excited and tells him "I want a baby brother" I can here the shock in his voice on the other end of the line as he tells her "No you can't have a baby brother" so she gets the sadiest look on her little face and hands the phone to me and says "Him said no" and then she cries. I felt so bad for her but on the upside she has not asked for one again. Hoping she forgot she wanted one, since we really can't give her one.