T., the only advice I have is this:
Think of your current children FIRST. That means setting aside time to evaluate a few very pertinent things:
Do you have the time to dedicate to them NOW to teach, train, etc.
Do you have 529 plans set up for their very real very future college plans?
Do you contribute to those plans every month? If not, why?
Also evaluate the "disaster" you mentioned and how another child would impact that situation. Be very honest, and take your loved ones concerns seriously. I have found older moms (grandparents, older coworkers) seem to have the best foundation for looking back and knowing...what they would have done...what they would not have done.
I suppose my concern is financial, which may be "worldly" and "unimaginative"; however, children that exist NOW deserve the very best, and if you are not financially secure to care for their needs, do not risk "disaster" a second time.
;)
V.