It's depressing that "co-parenting" is even a word. Children ARE resilient, but I think too many people use that as an excuse to absolve themselves or others of responsibilities, don't you agree?
From reading everything you're posting about your D, you're doing a great job, PS.
As far as a BF test, from what I understand, the best method is still using calipers. I think your GP can do it, hopefully PM will chime in with some other solutions. I'm glad you're not resting on your laurels! Keep setting new goals!
