Hi there,
I had GD with my 3rd DS and I was fine afterwards, then late last year I was feeling off and asked for blood test... now I have type 2 diabetes!
My mum has it and my grandma (dads side) has it, I am also overweight which doesn't help. From what I understand it is not necessarily weight related either - sometimes it is about what you eat and other times just plain bad luck! (I have a friend who has it and if she is not at all over weight!)
As for TTC - I am TTC at the moment, once you have your sugar levels all under control it is more safe, there are more risks than a normal pregnancy but the main problem is if you have high sugars it can effect the developing baby. (which is why they have to be closely monitor you)
You can got to "pre conception clinics" I beleive as well where they can give you help and will give you the "green light" for conceiving.
I hope it all goes well for you, my Dr has been so great with the whole thing and with a little more knowledge and help from the nurse I have my levels under control. Good Luck!