If someone in the maternity ward had come up to me after my daughter was born and asked me if I consented to a blood test, I'd think it was a really weird thing to ask consent for, which is probably why no one asked as far as I remember (maybe it was buried in a bunch of legalese or something). Has a baby ever suffered any sort of grievous harm from a blood test? It's like asking for consent to wash the kid after it's born. No one asked us for consent to do that either, which is probably good because neither of us were exactly in the right mind to think about such things what with me seeing something with 50% of my DNA coming out of my wife's body and her suffering through something with 50% of her DNA coming out of her body.