I went through that stage where I wanted another sibling, but it was kinda for selfish reasons. My parents were older and over-protective compared to my friends' parents, so I felt a sibling would take some of the attention off me. My relatives lived in other states, so my friends were all I had. When I whined like the 3rd time about a sibling, my mom explained that they tried to have another one. I was surprised to learn they tried, and I never mentioned it again, and I never resented them. Looks like I'll be explaining the same thing to my daughter.