Right now, you’re able to select the appropriate gender marker on your passport without a note from a medical professional (and a passport can be used in the vast majority of situations you’d use a birth certificate) but because the self select gender marker was done by executive action, it’s extremely likely to be reversed when Trump takes office.
Also, having one might be a good idea in general.
Get a passport card. It is legally the same as a passport book within the US (it can also be used for international land and sea travel within North America). It’s only $30 to apply and a $35 issuance fee. $65 in total for a piece of RealID-compliant identification valid worldwide for ten years.