About the transgender standpoint, maybe I’m talking out of line here, but gender does matter! If it was all inconsequential, there would be no queer movement. Celebrating that you’re going to have a boy does not mean you will not be supporting them in whatever gender indentity they will later identify as.
Nobody here is claiming that gender doesn't matter, though! You're right, gender is clearly not inconsequential. The problem is that gender is a socially constructed category into which people place themselves depending on how they identify. So when you get the word from your doctor that your unborn baby has XX chromosomes, you still have no idea what gender they will have. Celebrating that as proof that your child will later identify as a girl only reinforces unfounded societal expectations that their gender identity must correspond with their genitalia (which does kind of imply not supporting them if they identify with a another gender identity later)! At best, celebrating what genitalia your child will have is pretty weird; at worst, it's deeply transphobic.