Of course, one of the biggest differences you can make in your child's life involves deciding to have more kids. Is Jon an "only?" My DS is. If you Jon is an only, and there is a possibility of "more where he came from," I would encourage you to think in this direction.
Why?, well,in general, two of my favorite Mom-resources have said how useful it was. My reaction to raising my own "worried boy" was to shelter him from the stress of siblings and I didn't feel the urge until he was 5 years old. Turns out that sometimes siblings are similar enough that they can share so much with each other. They tend to be within 15 points of IQ, so there is much less of a spread than in a classroom of neighborhood. Mostly though, having more than one child limits the Mom's ability to "make everyone happy" all the time. It's as though having another child sends the message, "I believe in your ability to cope with this." Plus, protecting someone even younger is a great way to calm our own self, haven't you found that? I know I have.
Trin
Well, Trin, I usually agree with you, but I have a completely different take on this one. As a counselor who works with families, I have found that the best reason to have another child is because you and your partner really want one. When a parent has a child *for* someone else, such as to help another child, they are setting themselves up for some real disappointments--what if the children really don't get along? what if the second child has serious medical needs which puts a huge financial and emotional stress on the family? I have seen these things happen and the parent who decided to have a second child for the first child often has a much harder time dealing with the consequences than if they have the second child because they really want the second child. It can turn out well, of course, but I've seen it turn out very badly, with lots of guilt, anxiety and pain. That's my professional experience.
Here's my personal experience. I have 2 older siblings; we are all HG+. I found growing up in this circumstance very difficult. Because what I am about to say sounds very harsh, let me preface my remarks by saying my siblings are good people and we have a pretty nice set of parents who did a good job with us, but that does not take away the problems we had. My older brother was very smart, inquisitive, somewhat anxious, and perfectionistic. There is no doubt in my mind that he had a hard time adjusting to losing time with his parents when we younger two were born. He missed the intellectually stimulating conversations he had had with the adults who were now too busy to talk to him. I believe that he coped with this stress by over-identifying with his parents. He took on the role of mini-parent, but he lacked the perspective to be a good parent. His anxiety and perfectionism made him over-protective and tyrannical, all under the guise of being an ideal older brother. I grew up with him criticizing and mocking every thing I did; nothing was good enough unless it was just like he did it. I have tons of examples, but I will spare you. It was not until many years later that my parents had a clue how harsh he was with us; they just thought he was a devoted older brother. DH, the youngest of 4 gifted kids, shares almost the exact experience. This probably happens in non-gifted families too, but, I think it can be way more extreme when the oldest is very gifted and has perfectionist tendencies. The gifted older also has many more subtle ways of manipulating the family--the bullying was mostly psychological and under the guise of doing what is best for us.
I will also add that my parents often felt that they were not able to adequately nurture our gifts and advocate for all 3 of us because of limitations time, money, and energy. A family should consider all these things when deciding on family size.
There are tons of ways to help an anxious child that I think are more effective than bringing on sibs (I think that made my brother's anxiety worse). I suggest The Anxiety Cure for Kids as a great place to start. It helped us immensely.
And, Jon's Mom, sorry for this unsolicited treatise on family size. I know that wasn't the question you asked; I just get all goofy when I hear someone suggesting an appropriate family size for someone else--it's just way too personal a decision.
And Trin, this one disagreement doesn't make me respect your other ideas any less. I appreciate all your contributions!!