Please can I join your thread?
At the moment we're trying to make the final decision to TTC#2.
DD has just turned 6, I'm 41 (just
) and DH is 39.
If everything was Ok it would be a forgone conclusion that we would just be TTC. But things have been difficult with DD.
My PG was difficult (emotionally) as we got a high risk result from the 12 week scan (1:35). I had a CVS where they didn't take enough blood so couldn't get a result so had to have an Amnio at 18 weeks. Luckily all was clear.
But then randomly, the Consultant still doesn't know why, I got Gestational Diabetes at 28 weeks and straight away was on insulin injections 5 times a day. It was a complete shock because I was a size 10 woman who ate really healthily.
DD was then born by Ventouse and the procedure damaged DD's eye. So much so that she will need cosmetic operations every few years to make her eyes look 'normal'. Since then she's had problems with her ears and she is also very small (DH's side of the family) for her age. Because I'm tall she went through loads of different tests to find out why she is so small. All came back fine but she knows that she's really small and she gets upset by it.
So all of these things have made us doubt whether we should have another one. I have a good friend who has a beautiful DS, the same age and size as DD. His younger brother is much taller and the lad is so self-conscious about his height. So I do worry about having a DS in case he's as tiny as DD.
These things may all sound trivial to others and shouldn't matter when you're desperate for another child, but I see my DD struggling with these things on a daily basis so I'm having to consider them.
But these are very slightly outweighed by the fact that DD is DESPERATE for a baby DSis or DBro. She talks about it every day.
We did try for 3 years and other than 1 MC, not a sniff of a PG. Went through all the tests and a Laparoscopy and all was/is fine. Maybe it's an emotional blocker... 
Sorry to waffle...
Good luck to us all!!!