Until when, or if, the “child” becomes an adult and is surgically changed to whatever the gender du jour, legal documents identifying he or she should reflect the gender they were born with, not what Mom wants it to be. Stupid woman.
CSI Miami did a show where they were desperately searching for a perp an eyewitness had identified, but the DNA evidence was of the other sex. Same thing here. DNA doesn't change, no matter what kind of surgery.