One of my best friends just won't let go of the idea that I "need" to have another baby....specifically a girl ( like I can control that). I know she means well but she doesn't get how much it stirs up all the guilt I carry with me surrounding DS going it alone when we are old. This is my only reason for feeling any guilt but it is a big one and she just stirred that right up today

I guess I just need to vent to people who understand where I am coming from...
Chemical Pregnancy 2001, Married 8/8/09, TTC April 2011, BFP 5/8/11, Missed M/C @ 9wk5d, D&C 6/21/11 BFP 11/13/11 Chase Everett born at 29wks 0 days on 5/7/12 at 2 lbs 14 oz, 14 1/2 inches long.
Re: Vent
Like Arcadia said, a sibling isn't a guaranteed companion. A lot of siblings' relationships are destroyed by something like the death of a parent (fighting over the estate, etc). The onlies I know in life have awesome friendship networks and seem to have more support than most of my friends with siblings.
As for your guilt, I am an only and have never once questioned it. I love it. I think, for those of us onlies, you don't know what you don't know. Singleton life is all we know, so we, in general, are happy with it. I loved being an only and really appreciate my parents making a decision to provide me with the resources they deemed the most important (their attention, finances etc) over a sibling. I see so many screwed up siblings that I know even when they pass away, I am in a better position than most.
Your friend needs to shove it.
Burned by the Bear