Adopting out of birth order - - who has done it?

I'm curious about this, too, for slightly different reasons. We have three boys 15, 13, 11, and adopted a girl who is now almost 2. We are thinking of adopting again, but I don't know whether it's better to hope for a child who is older than our little girl, or younger. When we adopted the first time we were told that it is not a good idea to adopt kids close to your bio kids' ages (at least with our age grouping), that you needed to have at least five years between the youngest in one sibling group and the oldest adopted group of kids. That way they don't feel displaced from their birth order, and you avoid lots of sibling rivalry issues. I would like to know what folks' experiences have been with this. Looking forward to the replies!

We adopted a sibling pair (11 and 13 at placement now 13 and 15). At the time, our bio children were 7 and 10 (now 9 and 12). We had always planned to adopt, although we had learned early on that it wasn't recommended to adopt out of birth order. It is a very long and complex story as to how we ended up with our two - suffice it to say that it was God's hand that chose them for us. That said, I would not recommend it. Biodd (Bob, don't ask!) said she was fine with losing her place as oldest. She changed her mind. While add (Kitty) is a year older than Bob, she is emotionally and in many ways, developmentally younger than Bob (as is her brother, Bear - due in part to their many moves, both in foster care and with biomom, their mental illnesses and the abuse and neglect they suffered). It didn't help that the girls were in the same grade at school (Bob is one of the youngest in her class due to her Summer birthday - Kitty is a year behind because of all the moves she did with biomom). Bob is also very tall for her age 5'8" and Kitty is only 5'3" this irritates both girls for some reason. We have higher expectations for Bob because although she is chronologically younger, she is VERY mature for her age. This gets on her nerves too. Our ads (Bear) is the oldest and was the oldest in biofamily, but this has been an even bigger problem. When he came to us, he had undiagnosed bipolar disorder, he also has RAD, ADD, PTSD, and many other issues. He was a VERY angry and aggressive young man (already 5'9" and 200lbs and had been since he was 11). He attacked Hubby several times and ALL the children were afraid of him. Luckily he never hurt or abused (physically or sexually) any of the other children, but if he had, it would have been very hard to protect them. I love my family, and would not change a thing now, but it has been a VERY hard 2 years and if I had it to do over again, I would not have done it. I do NOT recommend adopting out of birth order. It is difficult to protect younger children and hard to explain to them why their older siblings are not able to handle the same expectations and responsibilities. Just my $.02!