By some state law, any adult by the following definition can give legal consent:
18+ y/o
Minor parent (for self and child)
Emancipated minor (married, military, or court decision)
Minor in case of pregnancy/STD/substance use
Anyone in an emergency.
The small group leader we had made an interesting comment about the above definition: "So pretty much, anybody who's done something terribly wrong is considered an adult and can give consent- and those who are being good kids and staying home can't." A little ironic, eh?