Anyone choose to have just one child?

My DH and I are talking about hoping for a special needs child through foster care, maybe older child. I guess the private adoption thing was a rough journey for us and we now have our baby. We still think we want another child though, we might just foster and see where it leads. We have a few friends who are foster parents and it seems to be a challange we are up to. Only you and your husband know how your family feels complete. I personally would want more than one child. We now have a 18 yr old, 15yr old and 2 mo. old~ I am hoping for two more, I think DH is hoping for one more. We'll see, we are getting older also.